If you hear the pitter-patter of little feet or scratching sounds in your walls, or if you find mouse droppings in your home, you could have a mouse infestation inside your walls. Ignoring the problem will only lead to continued population growth that could eventually pose a health risk. Extermination and cleanup are important to fully eradicating the problem.
Examine baseboards, floors and walls for holes that indicate the presence of mice. Mice can work their way through very small openings. The presence of mouse droppings and gnawed drywall or trim are indications that you’ve got mice inside your walls. Mice that live in walls don’t stay there -- they come out at night to forage for food.
Seal up all of the small internal holes that you find. You can use a drywall caulking agent or even board up the holes with plywood. “Funnel” the mice out of your walls through the single largest hole you find by baiting the opening with peanut butter.
Set traps where you find mouse droppings. Snap traps are a fast and humane way to rid yourself of mice. You can also use live traps and release the mice you catch outside. Avoid poison, which can lead to dead and decaying mice in your walls, as well as being a health hazard to children and house pets. Also avoid glue traps, which are inhumane.
Prevent future mice infestations through regular cleaning, and by keeping food tightly stored in your cabinets and cupboards.