How to get rid of mice

Before anything: confirm it is mice

Rice-grain droppings pointed at both ends means mice. Raisin-sized and blunt means rats, and nothing on this page will work — mice vs rats takes a minute and saves buying the wrong size of everything.

Step 1 — find the runways

This is the step that decides whether the rest works, and it is the one people skip.

Mice travel with one flank against a vertical surface and reuse the same routes every night. You are looking for:

• Droppings in a line, rather than scattered — that is a run, not a visit.
• Grease and dirt smears along a baseboard, at about the height of a mouse's shoulder. Hold a flashlight low and near-parallel to the wall and they become obvious.
• Gnaw marks on cupboard corners, food packaging, and the underside of doors.
• Shredded material — insulation, paper, fabric — collected somewhere warm and enclosed.

The productive places, in rough order: behind and beneath the refrigerator, under the sink, the back of the pantry, along the back wall of base cabinets, the garage wall shared with the house, and the airing cupboard or boiler space.

If you cannot find a run, slide a couple of monitoring glue boards into the gaps under appliances overnight. Lift them in the morning; the one that picked up hair or droppings has found your route. That is the one legitimate use for a glue board and it is covered in snap trap vs glue trap.

Step 2 — buy enough traps

Six minimum for one room. A dozen for a kitchen with an established problem.

This is the second decisive step and the most common failure. Mouse populations are larger than the sightings suggest, and a campaign that covers every run at once finishes in days, where a campaign with two traps drags on for weeks and teaches the survivors what a trap is.

Which trap depends on your house rather than on a ranking: plain snap traps by default, enclosed traps if a dog or a toddler can reach them, electronic traps if you cannot face the disposal. The full roundup has the picks for each case.

Step 3 — set them properly

Perpendicular to the wall, trigger end touching the baseboard. A mouse running the wall meets the trigger square. A trap laid parallel gets walked past.

A pea of peanut butter, pressed in. Not a spoonful — a large bait lets a mouse feed from the edge. In cold weather, a scrap of cotton wool tied to the trigger often beats food, because a mouse gathering nest material has to pull.

About six feet apart along an active run, with two side by side at the heaviest spot.

Handle traps with gloves — partly hygiene, partly scent.

Where to place mouse traps has the room-by-room detail, including the three places almost everybody misses.

Step 4 — check, reset, and be patient for five nights

Set in the evening. Check in the morning. Do not keep going back to look; each visit moves the trap and adds disturbance.

What a normal week looks like:

• Night 1-2: the bulk of the catching. Mice are curious about new objects and investigate within hours.
• Night 3-5: the tail. Numbers drop off quickly.
• Night 6-10: occasional catches, usually in one specific spot, which tells you where the remaining route is.
• Nothing for five consecutive nights: you are done with the trapping part.

If you are catching nothing at all by night three, the traps are in the wrong place rather than the wrong kind. Move them to where the droppings are, not to where you saw the mouse.

If you are still catching steadily after two weeks, you do not have a trapping problem — mice are coming in from outside, which is step 5.

Step 5 — seal the entries, or do this again next fall

Trapping without exclusion is a subscription. A house mouse gets through a gap about 6 mm across, which is a lot of gaps.

Walk the outside of the building slowly, at ground level, and look at:

• Where pipes, cables and vents pass through the wall
• The gap under the garage door seal and the thresholds of exterior doors
• Where siding meets the foundation, and any gap behind it
• Air bricks and crawl space vents with damaged mesh
• Where the dryer vent exits, which is often the single worst offender

Pack every gap with coarse steel wool or copper mesh and seal over it. Mice chew straight through expanding foam or caulk on its own; they do not chew metal. For larger gaps, hardware cloth screwed over the opening and then sealed.

Inside, close the route into the wall cavity: the gap around pipes under the sink, the space behind kickboards, and the hole where a cable enters a cupboard.

Step 6 — remove what they came for

Mice came for food and shelter. Pick both off:

• Dry goods into hard containers — glass, metal or thick plastic. Mice open cardboard and thin plastic without difficulty.
• Pet food out of the bag it came in, and not left down overnight.
• Birdseed out of the garage, or in a metal bin.
• Crumbs under and behind the appliances, which is where they actually are.
• Cardboard storage piles, which are nesting material with a free roof.

Cleaning up afterwards

Do not sweep or vacuum droppings dry. CDC guidance is to ventilate the area, wear gloves, spray droppings and nesting material with a disinfectant or a bleach solution, let it soak for five minutes, then lift with a paper towel and bag it. Wash your hands afterwards. The full CDC guidance is linked at the foot of this page and is worth two minutes of reading if there is a lot to clean.

What to skip

• Ultrasonic repellers. Here is what the testing found.
• Peppermint oil as a treatment for an active infestation. It has a narrow use in sealed, unoccupied spaces and is not a substitute for trapping — natural mouse repellents is honest about which is which.
• Poison indoors, for the reasons in mouse trap vs poison: you lose control of where the mouse dies, and the risk does not stop at the mouse.
• A cat. Some cats hunt mice. Many do not, and the ones that do can be poisoned by eating a mouse that ate bait somewhere else.

When to call a professional

This site exists so you can do it yourself, which is why it should say when not to:

• Droppings across a large area of an attic or unventilated crawl space — that is a respiratory-protection job before it is a pest job.
• A structural infestation inside walls you cannot open or reach.
• A problem that comes back within weeks of every treatment, which means there is an entry point you have not found and a survey is worth more than more traps.
• Any infestation in a household with someone immunocompromised.