How to Get Rid of Mice and Rats in the House Safely: Traps and Rat Poison

Scratching in the ceiling at night, or a bag of bread chewed open on the kitchen counter in the morning: that is usually how people find out they have a mouse. The first thing many of them do is walk to the nearest shop and buy rat poison or a glue trap. Either one can work. Either one can also cause a bigger problem than the mouse if it is used the wrong way, especially in a home with a crawling baby or a cat. We wrote this guide from our work as a pest control team, and we checked every number in it against sources such as the CDC, the US Environmental Protection Agency (EPA) and the University of California’s Integrated Pest Management program (UC IPM).

Mouse or rat? How to tell what is in your home

The easiest way to tell is to look at the droppings. House mouse droppings are 3 to 6 mm long with pointed ends, while Norway rat (sewer rat) droppings are roughly 2 to 2.5 cm. It matters, because the type of trap, where it goes and how many you need all depend on which one you have.

Three kinds usually get into homes:

	House mouse	Norway rat (sewer rat)	Roof rat
Size	Body 6.3 to 9.5 cm without the tail, weighs about 15 g	Body up to 28 cm, weighs roughly 200 to 500 g	Weighs roughly 140 to 280 g, tail longer than its head and body
Droppings	3 to 6 mm, pointed ends	Roughly 2 to 2.5 cm	About 1.3 cm
Tooth marks	Two grooves, 1 to 2 mm wide	3.5 to 4 mm	3.5 to 4 mm
Where it lives	Inside walls and cupboards, behind appliances	Burrows next to building foundations and under clutter; indoors, on the ground floor and in basements	Up high: storage lofts, false ceilings, inside walls and high cupboards
How far it goes from its nest	Rarely more than 9 m	30 to 150 m	90 m or more

The last row of the table is the one that matters most. If you see mouse droppings in the kitchen, the nest is probably in the same apartment: behind the fridge, inside a kitchen cupboard or up in the storage loft. A Norway rat, on the other hand, may live in the building’s light well (the air shaft between apartments) or in a street drain, and come up at night to eat before going back. With rats, deal with the way in first and the traps second.

Water is another difference. A Norway rat has to drink every day, from a puddle or from condensation on the pipes, while a house mouse usually gets enough water from its food. So a dripping tap under the sink, or an air conditioner dripping on the balcony, matters more when you have rats.

If you are not sure which one you have, photograph the droppings next to a pen or a coin so the size is clear, and send the photo to a pest control technician before you buy anything.

Signs of mice in the house

You will usually see signs of a mouse before you see the mouse itself, because it moves around mostly at night. The clearest sign is droppings: small black pellets with pointed ends, sometimes with hair in them, which turn up in cupboards, in drawers and along the walls.

Look in these places:

• The cutlery drawer, under the sink, behind the stove and on the pantry shelf with the rice and pasta. These are the usual spots for droppings.
• A bag of bread or lentils torn at one corner, a chewed cardboard box, or the bottom edge of a wooden cupboard door. Mice gnaw to open a way through, and also because their teeth keep growing and have to be worn down.
• The false ceiling or the wall at night, after the house goes quiet. Scratching there means something is moving above or inside.
• Dark smudges on a wall or pipe, always in the same place, left by the mouse’s fur as it rubs past on the same route every day.
• Behind boxes, in a drawer that rarely gets opened, or in the storage loft: a pile of shredded paper, fabric or cotton is most likely a nest.
• With a large or long-running infestation, a heavy, stale, musky smell in a room or storeroom.

Old signs or a mouse that is still there?

Gnaw marks and droppings can be months old. To find out whether there is activity now, clean the area using the safe method in the cleanup section below, then check again a few days later. New droppings after cleaning mean the mouse is still around. The CDC suggests the same test, and it saves you from buying poison for a mouse that left long ago.

If what wakes you at night is bites on your skin rather than scratching in the ceiling, that is a different problem altogether, and our bed bug guide covers it.

How do mice get into an apartment?

A house mouse can get through a gap 6 mm wide, about the width of a pencil, and a Norway rat can squeeze under a door with only 1.3 cm of clearance. Any gap around a pipe, under a door or in a false ceiling can be the way in, so finding it comes before anything else.

These are the indoor spots the CDC says to check first, as they look in a typical Egyptian apartment:

• Under the kitchen sink and around the drain pipe.
• Behind the washing machine, the fridge and the stove, and under the kitchen cabinets.
• Around the gas pipes, water pipes and electrical cables where they enter the apartment.
• The bathroom or kitchen floor drain, if it has no tight cover.
• The line where the floor meets the wall, and the corners at the bottom of cupboards.
• The air conditioner pipe hole and the exhaust fan opening in the wall.
• The front door and the balcony door, if there is a gap underneath.
• Windows that open onto the light well, and false ceilings with openings for spotlights or air conditioning.

A high floor is no protection. A house mouse can jump up to 30 cm from the floor onto a flat surface, and roof rats live up high anyway, moving along pipes, beams and high shelves.

What to seal the gaps with

Pack small gaps with steel wool and put silicone or filler around it so it stays in place, or use spray foam. Larger openings need sheet metal, cement, or metal wire mesh with holes smaller than 6 mm, cut to fit around the pipe. Under doors, fit a rubber strip or a door sweep, especially on the balcony door and on a kitchen door that opens onto the back stairs. Floor drains need a tight metal cover.

A towel under the door or a piece of cardboard over a hole will do for one night, but mice chew through paper, fabric and cardboard easily, so don’t count on them as a permanent seal. Seal the gaps that lead outside early on, so new mice don’t get in while you are trapping the ones already inside.

Why do mice multiply so fast?

A female house mouse can give birth 5 to 10 times a year, about 5 or 6 young each time, and pregnancy lasts only 18 to 21 days. The young can breed 5 to 6 weeks after birth. So if a mouse is pregnant today, her young could be having litters of their own in about two months.

Norway rats are a bit slower, but not by much: a female has 4 to 6 litters a year and can raise 20 or more young a year. Roof rats have 3 to 5 litters a year, with up to 8 young each time.

These numbers explain two things people say all the time:

1. “I caught a mouse and there’s still one around.” If a single female got in two months ago, there is probably a whole family inside by now.
2. “The mice came back after I got rid of them.” As long as the way in is open and food is easy to find, any mouse from the light well or the apartment next door will find the same comfortable spot and start over.

And because a house mouse rarely goes more than 9 m from its nest, droppings in your kitchen every day mean the nest is very close: inside the kitchen cupboard itself, under the bathtub, or behind the boxes in the storage loft.

How to get rid of mice in the house, step by step

Getting rid of mice takes 4 steps, in this order: find where they are active, take away their food, water and hiding places, seal the gaps, and set traps on their path. Poison is the last step, used only if the problem continues, and then only inside a locked bait station. Skip a step and the mice come back.

The first night

1. Take a flashlight and look under the sink, behind the fridge and the stove, and at the back of cupboards and drawers. The spot with the most droppings is where the first traps go.
2. Lock the food away: rice, pasta, lentils and flour go into heavy plastic or glass containers with tight lids, and bread goes into a closed box instead of sitting in its bag on the counter. Don’t leave the cat’s food in its bowl overnight.
3. Keep the trash in a bin with a lid that closes properly, and take it out every day, especially when there are food scraps in it.
4. Fix the dripping tap, dry the area under the sink and cover the drains.
5. Set at least two traps in every spot that shows activity, the way the next section explains.

The first week

• Check the traps every morning, and remove any dead mouse right away, wearing gloves.
• Clean each trap and put it back in the same spot, and keep going until the activity stops.
• Start sealing the gaps you found, beginning with the ones closest to the activity.
• Clear the clutter: old boxes in the storage loft and on the balcony, bags of clothes left on the floor, and anything else a mouse could hide behind.

When can you say they’re gone?

If a full week goes by with nothing in the traps and no new droppings after cleaning, the mice have most likely gone. That is the standard the CDC gives. At that point, take the traps out of places children can reach, and leave one or two in the storage loft or under the sink, somewhere closed off, as an early warning.

If you live in an apartment building

A Norway rat can travel up to 150 m from its nest to feed, so it may live in the light well, the trash room or the stairwell and visit several apartments. In that case, treating your own apartment reduces the problem without ending it. Talk to your neighbors or the owners’ association, because the building’s trash, the light well and the shared drains need one plan for the whole building. The University of California makes the same point: keeping rat numbers down over the long term takes work across the whole area.

Mouse traps: which type to use and where to put them

The ordinary snap trap is the one the CDC recommends for homes. Set it on the floor so it forms a T with the wall, baited end against the wall. The CDC says not to use glue traps or live-catch cages, because a mouse caught alive panics and urinates, and that raises your chance of getting sick.

Trap type	Pros	Cons	Our view
Snap trap (wood or plastic)	Kills at once, cheap, can be cleaned and reused	Has to be kept away from children’s fingers and cats’ paws	First choice at home
Glue trap (glue board)	Easy, fits anywhere	The mouse urinates while stuck, larger rats often avoid it, and birds and kittens get stuck on it	Snap traps are better; if you use one, check it daily and keep it away from animals
Live-catch cage	No poison and no blood	The mouse panics and urinates, and you still have to deal with it afterward	Not practical in an apartment

What’s wrong with glue traps?

Besides the CDC’s point about urine, there are two more problems. First, larger rats often avoid glue boards, so most of what they catch are young ones while the breeding adults stay. That comes from the University of California, which also doesn’t recommend glue boards for rats unless a professional is using them. Second, they make the animal suffer. That is why England banned their use against rodents in 2024, except under a license that pest control professionals can get for exceptional cases such as operating rooms, and the government there describes them as inhumane.

If a cat or a bird gets stuck on a glue board, cooking oil helps loosen the glue from the fur or feathers. After that, take the animal to a vet.

Where to put traps, and how many

Mice run along walls, so a trap belongs right against the wall: at a right angle to it, with the trigger very close to the wall. If you have to set it parallel to the wall, put two side by side. Start with enclosed spots: behind the stove and the fridge, at the back of cupboards and drawers, and in the storage loft.

How many traps you need, and how far apart, depends on the species:

• House mouse: no more than 3 m between traps in an area with activity. Set two traps side by side, 2.5 to 5 cm apart, so that a mouse that jumps over the first one lands in the second.
• Norway rat: 3 to 6 m between traps, and a heavy infestation may need 12 traps or more in one house.
• Roof rat: put traps up high as well, on top of cupboards, on the storage loft shelf and next to high pipes, and fix them firmly in place.

What to bait them with

The CDC recommends chunky peanut butter or mutton fat, in a very small amount, and the University of California puts that amount at the size of a pea. A small piece of whatever the mice are actually eating in your home also works. If someone at home has a peanut allergy, use the fat, or a small piece of cotton wool, because a female mouse building a nest will take the cotton.

Rats are suspicious of anything new

Norway rats avoid anything new on their path, whether a trap or food, for the first few days and sometimes for weeks. So a trap that catches nothing in two days hasn’t necessarily failed. The CDC and the University of California both suggest the same fix: put the traps out baited but not set, leave them until the bait has been taken several times, and only then set them. If the bait is gone from every trap, double the number of traps.

Trap safety

Check traps every day, and wear gloves to remove a dead mouse. If you plan to reuse the trap, the CDC says to drop the mouse into a bag, soak the trap in disinfectant for 5 minutes, then rinse it and let it dry. Put traps where children and pets can’t reach them, or inside a box made to hold traps.

Rat poison: the types and how they work

Rat poisons fall into two groups. Anticoagulants stop blood from clotting and cause internal bleeding; the rodent dies 4 days to 2 weeks after it starts eating. The other group acts on the nerves, heart or kidneys, or releases a toxic gas in the stomach, and some kill within hours. Both are dangerous to children and animals.

We won’t name products, active ingredients or mixing ratios here, and that is deliberate. The point is to understand how the types differ and to know what to ask, not to pick a product from an article.

Type	How it works	How long it takes in the rodent	Main risk at home
Multiple-dose anticoagulant	Gradually stops the blood from clotting	The rodent has to eat it several days in a row; death in 4 days to 2 weeks	In people, symptoms can be delayed by up to 5 days
Single-dose anticoagulant	The same idea, but stronger	One day of feeding may be enough	It stays in the poisoned rodent’s liver for weeks, so a cat or dog that eats the rodent can be poisoned
Non-anticoagulant	Affects the nerves, raises calcium to levels that damage the heart and kidneys, or releases a toxic gas in the stomach	Hours to a few days, depending on the type	Some of these have no specific antidote, and treatment means supporting the body in hospital

Why locked bait stations?

A bait station is a heavy plastic box that locks, with an opening sized for a rodent and the bait inside. The rodent goes in to eat, and a child or a cat can’t get to the poison. In the United States, the EPA no longer allows poison to be sold to consumers as loose pellets; it has to come ready to use inside a bait station. For pest control companies, tamper-resistant stations are required anywhere a child under 6 or a pet could reach.

The station also solves a second problem: the bait stays dry and you know where it is, so you can tell how much the rodents ate and from which station. That is how we work: locked, numbered stations, placed away from children and animals, and checked on every visit.

Dangerous mistakes with rat poison

• Mixing powder into food and leaving it out in a dish. This is the most dangerous form in a home: the dish is open to any child or cat, and the powder spreads onto hands and floors.
• Moving the poison out of its package, into a yogurt pot or an unlabeled bag. The Poison Control Center at the Children’s Hospital of Philadelphia (CHOP) advises keeping poison in its original container, which makes a real difference if there is an accident and the doctor needs to know the ingredient.
• Scattering loose pellets on the floor or in the storage loft. The same center warns that bait often ends up where children and pets can reach it.
• Leaving dead rodents where they fall. The University of California says one dead rodent may be enough to poison a pet, so collect them every day, wearing gloves.
• Adding more because you haven’t seen results. The slow type takes 4 days to 2 weeks, and extra bait only raises the risk to the people and pets in the home.
• Keeping the poison’s location to yourself. Everyone who lives in the home, including anyone who helps with the cleaning, needs to know where the stations are.

Why poison alone usually isn’t enough

1. The way in is still open. Poison kills the mice inside, and the gap lets new ones in.
2. Uncovered food competes with the bait. If the bread bag is right there, the mouse doesn’t need the bait.
3. Rodents avoid new food, Norway rats especially, for the first few days and sometimes for weeks.
4. The rodent dies inside the house. The popular idea that poison sends rats outside looking for water, so they die out there, isn’t accurate. The University of California says house mice stay close to their nest, so a poisoned mouse usually dies inside the building, and that is where the smell from the wall or the false ceiling comes from.

The strongest rat poison in Egypt?

We won’t recommend a product. The poison that is “strongest” on a rat is also the most dangerous for a crawling baby or a cat that wanders around the house. In the United States, the strongest slow-acting poisons (the single-dose kind) are no longer registered for consumer products at all and are sold to pest control companies only.

So “which one is strongest?” is the wrong question. Ask instead: does the label state the ingredient and the instructions? Is the bait inside a locked station? Is it on the path the rodent actually uses? And has the gap it came in through been sealed?

What is “black” rat poison?

“Black poison” is a name used in the market, not a scientific term, and it usually means a dark powder that gets mixed into food. The color of a poison doesn’t tell you its type or its strength. Some products have a blue or green dye added on purpose, so that it shows if a child or a pet eats some; the color is a dye, not the active ingredient. The label is what tells you the type. Any loose powder, black or otherwise, doesn’t belong in a home, because it can’t go into a locked station and it spreads easily onto hands and food.

How long does rat poison take to kill a rat?

Anticoagulants kill a rodent 4 days to 2 weeks after it starts eating them, according to the EPA, and some fast-acting types kill within hours. The University of California says bait generally takes a few days to show any effect, and that Norway rats can take days or weeks before they even go into bait stations. So if you see no result after two days, that is normal.

Rat poison, children and pets: what to do if someone swallows it

If a child or anyone else swallows rat poison, call the ambulance on 123, go to the nearest hospital and take the package with you, even with no symptoms. Anticoagulant symptoms can be delayed by up to 5 days, and cats and dogs can be poisoned by eating a poisoned rodent without ever going near the bait.

Why does the package matter? Because the treatment depends on the type. Anticoagulant poisoning has a hospital treatment that reverses its effect, while some fast-acting types have no specific antidote, and treatment means monitoring and supporting the body. The ingredient name on the package saves the doctor time. If you don’t have the package with you, take a photo of it, or of the station or the bag.

Before you call the ambulance, or as soon as you reach the hospital, have this information ready: the age and approximate weight of the person who swallowed it, the product name, the time it was swallowed, and the amount, as best you can estimate.

Symptoms to watch for

The most common type is the anticoagulant. Its symptoms are signs of bleeding, and they may show up late:

• Nosebleeds or bleeding gums, or a small cut that won’t stop bleeding.
• Bruises on the skin without any knock.
• Blood in the urine or stool.
• Vomiting blood.
• Paleness, drowsiness or confusion.

The other types cause different symptoms depending on the type, such as vomiting, shortness of breath, seizures, or thirst and frequent urination. Any of these after someone has been near rat poison means calling the ambulance right away. Even with no symptoms, the doctor may ask for a blood test a few days after the swallowing to check that the blood is clotting normally.

If the poison touched the skin

Wash the skin with soap and water, then read the first aid instructions on the package and follow them. If a child touched the bait and then put a hand in their mouth, treat it as swallowing and call the ambulance.

Cats and dogs: two ways to get poisoned

A cat or a dog can be poisoned in two ways: by eating the bait itself, or by eating a poisoned rodent. The second is called secondary poisoning, and it is the reason proper rodent control picks up dead rodents as soon as they turn up. Some poisons stay in a rodent’s liver for weeks, and the University of California says a single dead rodent may be enough to poison a pet.

The signs of poisoning in an animal vary with the type: weakness and lethargy, pale gums, trouble breathing, or tremors and seizures, and with one type the vomit smells like garlic. If you think your cat or dog ate rat poison or a dead rodent, go straight to the nearest vet and take the package or a photo of it.

How to prevent an accident in the first place

• If there is a child under 6 or a pet in the home, start with traps and sealing gaps, and keep poison as the last resort.
• Any bait goes inside a locked station, and the station is fixed in place.
• Store poison in its original package, in a high cupboard that locks, away from food.
• When you move into a new apartment, check the storage loft and under the sink for poison the previous tenant left behind.
• If you hire a pest control company, ask for the name of the product they used and keep a note of it.

Do ultrasonic repellents and smells really keep mice away?

No. No sound device or smell has been shown to clear a home of mice. The University of California says rodents quickly get used to any sound that repeats, and that no repellent has solved a rodent problem for more than a very short time.

Ultrasonic devices

These devices give off a high-frequency sound that people can’t hear. The trouble is that the sound travels in one direction and fades quickly with distance, so it reaches only a small part of the room, and in the end the mice get used to it. There is little evidence that sound, magnetic or vibration devices drive out or control mice that have already nested in a home.

Peppermint, cloves and chili

Peppermint oil, cloves, chili and garlic are some of the most popular remedies on YouTube. A strong smell may make a mouse change its route in one spot for a short while, but no scent repellent has been shown to solve the problem. In California, there is no registered repellent that works against rats at all. The smell fades, and the mouse comes back to the same spot as long as its food and its nest are still there.

What you would spend on an ultrasonic device goes further on steel wool and silicone to seal the gaps, plus a few snap traps.

How to clean up mouse droppings and urine safely

Don’t sweep or vacuum mouse droppings, because that can send germs into the air. Open the windows for 30 minutes, put on gloves, and spray the droppings with a disinfectant or a bleach solution (1 part bleach to 9 parts water) until they are soaked. Leave it for 5 minutes, then pick them up with paper towels.

That may sound like a lot of fuss over a few droppings. According to the CDC, rodents spread diseases such as leptospirosis, salmonella, rat-bite fever and hantavirus through their urine, droppings, saliva and bites, or through food they have contaminated. You can’t tell by looking at a mouse whether it carries a disease.

Cleanup steps from the CDC

1. Open the doors and windows for 30 minutes before you start, and stay out of the area during that time.
2. Put on rubber or plastic gloves.
3. Mix a fresh solution each time: 1 part bleach to 9 parts water, or use a product labeled as a disinfectant.
4. Spray the urine and droppings until they are soaked, and leave them for 5 minutes, or for the time stated on the disinfectant.
5. Pick them up with paper towels and throw them into a trash bin with a lid.
6. Wipe down the whole area with disinfectant: the floor, the shelf and any surface the mouse ran across.
7. Wash your gloved hands with soap and water or disinfectant, then take the gloves off and wash your hands with warm water and soap.

Throw away any food you find gnawed, or with droppings next to it.

A dead mouse in the house

Put on gloves and spray the droppings around it with disinfectant. Put the mouse (and the trap, if you are throwing it away) in a plastic bag and tie it, then put that bag inside a second bag, tie that one too, and throw it into a trash bin with a lid. The CDC also advises putting insect repellent on your clothes, shoes and hands when you handle a dead rodent or a nest, because rodents carry fleas.

Dead mouse smell inside a wall or ceiling

This is one of the worst side effects of using poison indoors. A mouse that dies inside a wall or above a false ceiling can’t be reached unless you open it up. The smell lasts until the body decomposes and dries out, and nobody can give you a fixed time for that. What you can do is air the room well and find the spot where the smell is strongest. If it is near a spotlight or an air conditioning opening in the false ceiling, you may be able to reach the mouse without breaking anything. If the smell doesn’t ease, a pest control technician or a plumber can locate the spot and open a small hole.

This is why traps are usually the better choice inside an apartment: the mouse is caught in a known place, and there is no body rotting inside a wall you can’t get to. The University of California recommends traps inside buildings for exactly this reason.

When do you need a rodent control company?

Call a rodent control company if traps have been out for two weeks and new droppings still appear after cleaning, if you can’t find the way in, if the scratching is inside the false ceiling or a wall, or if you have children and pets and need bait. A restaurant or food store needs a program from the start.

A quick checklist. If even one of these applies to you, a phone call will save you time:

• New droppings after two weeks of trapping and cleaning.
• Mice showing up in more than one room, or on more than one floor.
• Noise inside the false ceiling or the wall, which means the nest is somewhere you can’t reach.
• A large Norway rat (droppings of 2 cm or more), especially one coming from the light well or the drains.
• A dead rodent smell whose source you can’t find.
• A young child, a cat or a dog at home, and you would rather not handle poison yourself.
• A food shop, restaurant, warehouse or factory.

How our visit works

The Elalmanya Biology team starts by finding the rodents’ path and the place they get in, because sealing that gap matters more than the bait. Then we choose between traps and bait stations to suit the place: locked, numbered stations away from children and animals, sealing of the gaps we found, and a check of the stations on every visit. Same-day visits are available in all 27 governorates.

Send a photo of the droppings or the gnaw marks on WhatsApp at +201007892200, and tell us if there are children or pets in the home, so we can plan before we arrive. The full service details are on our rodent control page.

Rodent control for restaurants, warehouses and factories

In a restaurant or a warehouse, rodent control is an ongoing program rather than a single visit: locked, numbered bait stations around the outside of the building, traps inside the food and production areas, every possible way in sealed, and the stations checked on every visit so you can see whether activity is rising or falling, and where.

A commercial site differs from a home in several ways:

• Food is plentiful and easy to reach: sacks of flour, rice and sugar, and scraps in the kitchen. The bait has to compete with tastier food, so sealing the ways in and keeping the place clean are half the work.
• Norway rats need to drink every day, and condensation on cooling pipes, open drains and standing water under large fridges all give them that. Each of these sources needs to be dealt with.
• If the warehouse door or the delivery door has a 1.3 cm gap underneath, rats get through it, so a door sweep or a rubber strip along the bottom is essential.
• Boxes and sacks arriving from other warehouses may carry droppings or a nest. Inspect them as they come in, before they go into storage.
• In food preparation areas, traps suit better than bait, so no poison comes near the food and no rodent dies in a hidden corner of the kitchen.

Some advice for the manager, or whoever is responsible for the site:

• Keep stock on pallets or raised shelves, off the floor, with space between it and the wall, so staff can spot droppings and clean.
• Keep trash in bins with lids, and take it out of the building every day.
• Show staff what droppings and gnaw marks look like, and ask them to report them right away instead of quietly cleaning up.
• If your site gets inspected, ask the pest control company at the start which documents your type of business needs, so you know what can be provided as part of the service.

Send us the type of business and its approximate size on WhatsApp, and see the details of rodent control for homes and businesses.

Can you get rid of mice for good?

You can clear the mice out of your home, but nothing keeps new ones away forever while there is food, shelter and a way in somewhere in the building or the street. Sealed gaps and properly stored food make the result last, not stronger poison. If someone promises the mice won’t come back, ask how they’ll seal the way in.

The sign that the problem is solved is a full week with no catches and no new droppings after cleaning. After that, these habits make the difference:

• Once a month, look in the places nobody opens: the storage loft, under the sink, behind the fridge and at the back of the kitchen cupboard.
• Seal any new gap the same day it appears, for example after plumbing repairs or an air conditioner installation.
• Keep dry food in closed containers all year round.
• Clear old boxes and clutter off the balcony and out of the storage loft.
• If your neighbors have mice, talk to each other. A Norway rat travels up to 150 m from its nest, so to a rat the whole building is one house.

If the mice come back after a while, go back to the first question: how did they get in? The answer usually matters more than any bait.