The essentials in 30 seconds
Typical signs are small dark droppings, gnawed packets and cables, scratching at night in ceilings or cupboards and a musky smell. To get rid of them: set several snap traps along the walls where you find droppings, keep food in sealed containers, then block every gap with materials mice cannot chew, such as coarse steel wool, wire mesh and mortar or filler. Clean droppings wet, never dry: spray with disinfectant, wait, then wipe up with gloves on.
- A mouse fits through a gap of about 6 mm: check pipe and cable entries.
- Rats, or mice in garages, cellars or shared areas, are a job for pest control.
- Ultrasonic devices have little proven effect.
Signs of mice or rats
- Droppings: mouse droppings are small and dark, like grains of rice; rat droppings are much larger.
- Gnaw marks on packets, cupboard doors, cables and insulation.
- Noises of scratching or running, mostly at night.
- Greasy smears along skirting boards where they run against the wall.
- Nests of shredded paper, fabric or insulation in voids and furniture.
- A musky smell in closed spaces with large or long-standing infestations.
How mice get in
| Entry point | How to block it |
|---|---|
| Pipe and cable entries | Coarse steel wool packed in, then filler or mortar |
| Gaps under outside doors | Metal door sweeps or brush strips |
| Air bricks and vents | Fine metal mesh, keeping the ventilation open |
| Drains and inspection chambers | Well-fitting covers; grilles on floor drains |
| Cracks in walls or plinths | Repair with mortar |
| False ceilings and voids | Check from lofts, cellars or shared areas |
Avoid using expanding foam, plastic, rubber or wood on its own: mice chew through them.
How to get rid of mice step by step
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01
Find their routes
Droppings and smears show where they run, usually along walls.
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02
Remove food
Sealed containers, pet food put away at night and bins with lids.
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03
Set traps
Several snap traps close to the walls, where droppings are found and behind objects, baited with a small dab of peanut butter. Check them daily.
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04
Block the gaps
Once catches stop, seal entry points so new mice cannot come in.
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05
Clean and disinfect
With gloves, soak droppings and nests with disinfectant, wait about five minutes, then wipe up with paper towels and bag them.
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06
Keep watching
New droppings mean another way in or a larger population.
When to call pest control
- You have rats, not mice.
- They appear in garages, cellars, yards or shared areas.
- You still see signs after two or three weeks of trapping and sealing.
- There are young children or pets and you prefer not to use baits.
- You run a food business.
Mice: frequently asked questions
How do I know if I have mice?
Small dark droppings, gnawed packets or cables, scratching at night and a musky smell.
How small a gap can a mouse get through?
About 6 mm. Check pipe and cable entries and gaps under doors.
What is the best way to get rid of mice?
Snap traps along the walls, food out of reach and every gap sealed with materials they cannot chew.
Do ultrasonic repellers work?
There is little evidence. Mice get used to the sound and it does not reach behind furniture.
How do I clean mouse droppings safely?
Wear gloves, soak them with disinfectant, wait about five minutes, then wipe up. Avoid sweeping or vacuuming them dry.
When should I call pest control?
For rats, for mice in shared areas or if signs continue after two or three weeks.
Sources
Official and university guidance, checked on 24 October 2026.
- University of California IPM · House mouse ↗Signs, gaps of a quarter of an inch, materials mice cannot chew, trap placement, rodenticide cautions and ultrasonic devices.
- CDC · How to clean up after rodents ↗Soaking droppings with disinfectant for five minutes and avoiding sweeping or vacuuming.
- US EPA · Dos and don'ts of pest control ↗Safe use of pesticides at home.
Mice keep coming back?
Mark where you find droppings and every gap around pipes and doors before calling pest control.