Getting rid of mice requires three things done simultaneously: trapping the mice already inside, sealing the gaps they used to enter, and removing the food and water that attracted them. Skip any one of these steps and the problem comes back. A house mouse can squeeze through a hole the size of a pencil, just a quarter inch wide, so even homes that seem tightly built often have dozens of potential entry points.
Find How They’re Getting In
Before you set a single trap, grab a flashlight and inspect your home for gaps. You’re looking for any opening a quarter inch or larger, both inside and outside. Common interior spots include the gaps around pipes under sinks, the space behind appliances, the juncture where floors meet walls, areas around floor vents and dryer vents, and the corners of closets. In basements and attics, check around every utility line: electrical, plumbing, gas, and cable.
Outside, focus on the foundation line where it meets the ground, the edges of doors and windows (especially those missing weatherstripping), roof eaves and soffits, and anywhere pipes or wires penetrate the exterior wall. Mice leave signs near their entry points: dark greasy smudges from body oil, small droppings the size of rice grains, or fine gnaw marks on wood and plastic.
Seal Every Gap
For openings up to about two inches, stuff them with copper mesh. Copper won’t rust or stain your walls, and its tightly woven texture makes it extremely difficult for mice to chew through. You can tack, staple, or glue it in place, then cover it with caulk for a permanent seal. Steel wool works too, but it rusts over time and can leave orange stains on siding and drywall.
For gaps larger than two inches, repair them with standard building materials: hardware cloth, sheet metal, cement, or new lumber. Don’t overlook weep holes in brick exteriors or the gaps around air conditioning line penetrations. These are classic entry points that homeowners miss.
Set Traps the Right Way
Snap traps remain the safest and most effective method for controlling mice inside a home. The key mistakes people make are using too few traps and placing them in the wrong spots.
Mice tend to run along walls, so place traps perpendicular to the wall with the trigger end touching the baseboard. Set multiple traps, not just one or two. Mice breed quickly, and if you’re seeing signs of activity, there are more than you think. Good configurations include placing two traps side by side, or three in a row with the triggers alternating direction. Focus on areas where you’ve found droppings, near food sources, and along the routes between the two.
For bait, use a pea-sized amount. The classic choice is peanut butter, but mice can sometimes lick it clean without triggering the trap. The fix is to mix the peanut butter with something that forces the mouse to tug: crushed cereal, a single cashew pressed into it, or a bit of dry cat food kibble embedded in the dab. Alternatives that work well include a small piece of beef jerky, a chunk of gummy bear mashed onto the trigger plate, dried fruit, or a sliver of parmesan cheese rind. Cotton balls and short pieces of dental floss also work because mice collect soft materials for nesting. If you’re in a home with anyone who has a peanut allergy, skip the peanut butter entirely and use one of these alternatives.
Enclosed snap traps, where the mouse enters a small chamber and the trap kills it inside, are a good option if you don’t want to see or handle the dead mouse. You throw away the entire unit. Check traps daily. If a trap hasn’t caught anything in two days, move it to a new location.
Why You Should Avoid Poison
Rodenticides, commonly sold as bait blocks or pellets, carry serious risks that make them a poor choice for most homes. The most common type, anticoagulant poison, prevents blood from clotting. A mouse that eats it doesn’t die immediately. It wanders for three to five days, bleeding internally, and often dies inside a wall where it rots and smells for weeks.
The bigger concern is secondary poisoning. When a pet, hawk, owl, fox, or neighborhood cat eats a poisoned mouse, it ingests the toxin too. Because anticoagulants persist in the liver for months, even small repeated exposures accumulate. Between 2012 and 2024, New York State’s wildlife health program documented over 325 cases of rodenticide poisoning in wildlife, including red-tailed hawks, owls, raccoons, and foxes. Other types of rodenticide carry their own dangers: some cause seizures, others cause kidney failure. Children and pets are at direct risk of eating bait left in accessible areas. Traps and exclusion are safer and more reliable.
Cut Off Their Food and Water
Trapping alone won’t solve the problem if your home is still a buffet. Mice need surprisingly little food, about three to four grams a day, so even minor crumbs matter. Store all pantry food in glass jars, metal containers, or thick airtight containers. Mice chew through cardboard, thin plastic, and even soft metals like aluminum foil with ease.
Clean up crumbs and spills immediately. Put away pet food dishes overnight. Keep trash cans covered with tight-fitting lids and take garbage out regularly. Eliminate standing water from plant saucers, leaky pipes, and water cooler catch basins. Outside, remove bird feeders (a major attractant), pick up fallen fruit, and keep compost bins sealed. These steps don’t just support your trapping effort; they’re the reason the mice showed up in the first place.
Clean Up Droppings Safely
Mouse droppings can carry hantavirus and other pathogens, so cleanup matters. The most important rule: never vacuum or sweep droppings. Sweeping and vacuuming launch tiny virus-containing particles into the air where you can inhale them.
Instead, put on rubber or plastic gloves. Spray the droppings and any urine-stained areas with a household disinfectant (check that the label actually says “disinfectant”) or a bleach solution of 1.5 cups of bleach per gallon of water. Let it soak for at least five minutes. Wipe everything up with paper towels, throw the paper towels in a covered trash can, then mop the surrounding area with disinfectant. Wash your hands thoroughly after removing your gloves.
For heavy infestations with large amounts of droppings and nesting material, you need more protection: goggles, disposable coveralls, and a respirator with a HEPA filter. If that level of cleanup sounds like more than you want to handle, it’s a reasonable reason to call a professional.
When to Call a Professional
Most small mouse problems, a few droppings in one area, one or two mice caught over a week, respond well to DIY trapping and sealing. But certain signs point to an infestation large enough to warrant professional help: seeing mice during daylight hours (which indicates a large population competing for resources), hearing constant scratching or running sounds inside walls, finding multiple nesting sites, noticing strong musky odors, or catching many mice in traps without the activity slowing down. If your DIY efforts haven’t worked after two weeks, or the mice return shortly after you thought the problem was solved, a professional can identify entry points and population sources you’re missing.
A single treatment visit for a minor problem typically costs $295 to $600. Most professionals recommend a three-visit program, covering initial treatment plus two follow-up visits to monitor and adjust, which runs $695 to $1,000. The follow-up visits matter because they confirm the mice are actually gone rather than just temporarily reduced.