Are you noticing gnaw marks in the cabinets, hearing scraping sounds in the walls, or finding mouse droppings behind the stove? Then it is time to act. Mice reproduce quickly — a female can have up to ten litters per year with five to eight young per litter. The earlier you break an infestation, the easier it is to get it under control.
This guide goes through all the methods: from simple traps you set out yourself to when a pest control company is the right choice.
Start by confirming that it is mice
Before choosing a method it is important to know what you are dealing with. Mice leave clear traces: black droppings that are 3–6 mm long with pointed ends, gnaw marks on packaging and wooden surfaces, and a characteristic smell of urine that becomes more noticeable the more established the infestation is.
Are you hearing sounds in the walls? Mice are most active between midnight and dawn. Scraping and scurrying are typical sounds from mice, while rats produce heavier, more audible noise.
Method 1 — Snap traps (most effective for most people)
The snap trap is still the most tried and tested method for getting rid of mice. It is cheap, fast, and — with the right placement — very effective. Choose plastic traps or steel constructions over old wooden traps; they are easier to clean and last longer.
Placement is crucial
Mice move along walls and behind furniture — they avoid open spaces. Place the traps along walls and baseboards, behind the refrigerator, stove, and washing machine, under the kitchen sink, and in the bottom corners of cabinets. Position the trap with the bait end toward the wall, not facing out into the room.
The right bait
Chocolate, peanut butter, and dried fruit work better than cheese — it is a common misconception that cheese is the best bait. A small amount is sufficient; too much bait allows the mouse to eat without triggering the trap.
How many traps?
Use more traps than you think you need. A mouse has a territory of only 3–10 meters, but in a larger home with active movement it is better to have 6–10 traps placed out rather than 2–3. Check the traps every morning and change the placement if a trap has not caught anything after 3–4 days.
Method 2 — Poison baits (effective but requires caution)
Poison baits (rodenticides) contain anticoagulants that prevent the blood from clotting. They are effective but should be handled with care, especially in households with children and pets.
Place the bait stations inside concealed spaces — behind appliances, inside cabinets, in the crawl space — never openly accessible. A mouse that has eaten poison bait often crawls away before it dies, which can produce a smell of decay in walls and floors for a period.
Bear in mind that second-generation anticoagulant baits are required to break an established infestation — first-generation products such as difenacoum can take up to 10 days before the effect becomes visible.
Method 3 — Electronic mouse repellers and ultrasound
Ultrasound devices emit frequencies that mice perceive as disturbing. They are chemical-free, child-friendly, and require no active effort — you plug them in and let the device take care of itself.
The effect is greatest in combination with other methods, especially if mice have already established themselves in the walls where the ultrasound does not reach as easily. As a preventative option in spaces without active movement — storage rooms, garages, crawl spaces — they work well as a barrier however.
Repello's ultrasound-based mouse repeller works with bioacoustic signals and covers up to 40 m² per unit. It works well as a supplement to sealing and cleaning in homes where you want to avoid poison and traps entirely.
Method 4 — Seal the entry points
This is the step most people skip — and that is why the mice come back. A mouse can squeeze through a hole that is 6 mm in diameter. All gaps around pipes, cables, ventilation openings, and cracks in the base are potential entry points.
Seal with steel wool (mice cannot gnaw through it) combined with acrylic filler or sealant. Check specifically pipe penetrations in the kitchen and bathroom, gaps around pipes under the kitchen sink, and any holes in the foundation or basement wall.
Sealing is not an emergency measure — it is the final step that prevents new mice from getting in once you have dealt with the ones already inside.
When should you contact a pest control company?
There are situations where your own efforts are not enough:
- You have set out traps for two weeks without results and still hear sounds in the walls
- You find droppings in large quantities in multiple places in the house — a sign of a large colony
- There are mice in the crawl space or in walls you cannot access
- You live in a rental property — in that case it is the property owner who is responsible for the pest control
