Don't try to trap mice inside the wall. Lure them out to where you can catch them, then close the gaps so they can't slip back in. That scratching behind the drywall? It's mice using a warm, hidden corridor that links their nest to your kitchen. Getting them out comes down to three moves: find the activity, trap at the right spots, and seal the building shut.
Quick answer
Don't trap mice inside the wall. Lure them out instead. Set snap traps baited with peanut butter along baseboards near exit holes and check them daily. Remove food and water that draw them in, then seal entry gaps with steel wool and caulk once the scratching stops.
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Why Mice End Up in Your Walls
Wall voids are prime mouse real estate. They're warm, dark, and undisturbed, and they're threaded with runs that link the attic, the crawlspace, and your rooms. A mouse slips in through a tiny gap on the outside, then travels inside the wall to reach food and water without ever stepping into the open.
So what pulls them toward your house? Food left out, water they can reach, and clutter that gives them cover. A mouse can squeeze through a gap about a quarter inch wide, and it can gnaw through wood, drywall, and soft material once it's inside. A small entry point is all it takes.
First, Pinpoint the Activity
You can't catch what you can't find. Start by tracking down where the mice are. Listen at night, when they're most active, for scratching, scurrying, or gnawing. Note which wall the sound comes from and roughly what height.
Then look for physical signs near those spots so you can find their exits.
- Droppings along baseboards and inside nearby cabinets
- Greasy rub marks where mice squeeze through an opening
- Gnaw marks around holes in drywall, baseboards, or trim
- Small gaps near pipes, vents, outlets, and other wall penetrations, which is where their runs meet the room
Draw Them Out to Traps
Here's where most people go wrong. They try to trap the mouse inside the wall, where you can't place a trap, can't check it, and where a dead mouse turns into a smell problem. Set your traps instead at the points where mice leave the wall to look for food.
Place snap traps flush against the wall near suspected exit holes, behind appliances, and along baseboards where you spotted droppings. Bait them with peanut butter or another high-calorie food. Wear gloves so your scent doesn't tip them off, and check the traps every day. Mice are curious by nature, so a trap sitting on an active run usually gets investigated fast.
Remove the Reasons They Stay
A mouse keeps using a wall route for as long as it leads to a reliable meal. Take away the payoff and you slow their breeding while pushing the holdouts toward your traps.
Tighten up the basics across the whole house.
- Store food, pet food, and birdseed in sealed metal or glass containers
- Wipe up crumbs and spills, and skip leaving dishes or pet bowls out overnight
- Fix leaky pipes and faucets that feed water inside walls and under sinks
- Declutter storage rooms, closets, and the garage so there's no nesting cover
Seal the Gaps So They Can't Come Back
Once activity stops and the traps go quiet, exclusion is what makes the fix stick. Walk the outside and inside of the house looking for any opening a mouse could use. A quarter-inch gap is plenty.
Pack holes with steel wool, which mice can't chew through, then seal around it with caulk. For bigger openings, use hardware cloth or metal flashing. Give extra attention to the gaps where pipes, wires, and vents pass through walls, the underside of exterior doors, and any torn screens. One caution: seal interior wall holes only after you're sure the mice are out. Close one too early and you can trap a live or dying mouse inside.
When to Call a Local Pro
Mice in walls are tricky. The nest is hidden, the entry points are easy to miss, and a single sealed-in mouse can leave a smell that lingers. If the scratching keeps up after you've done the work, or you can't find the entry points, or you suspect a sizable nest tucked into a wall or attic, it's time to bring in help.
A licensed local exterminator can inspect the wall voids and attic, trap at the exact exit points, and run a whole-home exclusion that closes the gaps you'd never spot on your own. They'll also monitor afterward to confirm the mice are gone.