Seal the gaps the mice come through
Traps deal with the mice already in. Only sealing the gaps stops the next ones — and the two products people buy first are the two to avoid.
People dealing with mice in their own homes, arguing in public about what is cruel — and not agreeing. The page reports where that argument actually sits, including the parts that are uncomfortable and the parts nobody settled. The poison and glue-trap harms were checked against wildlife and veterinary sources rather than taken on trust.
You can catch mice all winter and still have mice, because catching them is not the thing that ends it.
Every mouse in your home came through a gap. Find the gaps and seal them, and the traps stop being a permanent fixture. Where a pipe or a cable enters a wall. Under a door. Around a vent. The join where the wall meets the ground. If you can get a pencil into it, something can get through it — and the materials that actually hold are steel wool stuffed into the gap, caulk over the top, or hardware cloth across anything larger. Expanding foam on its own is not one of them. They chew through it.
That is the whole strategy, and everything else on this page is either support for it or a warning.
The traps, briefly
Peanut butter on a snap trap, smeared rather than dolloped so they have to work at it. That combination came up more often than every other bait put together.
Set them along walls rather than in the middle of a room, because mice travel edges. If something is repeatedly taking bait without getting caught, change the mechanism rather than adding traps — one person’s persistently uncatchable mouse was dealt with by an electric trap after snap traps kept failing.
And a cat does reduce sightings, which is true and is not really a pest-control purchase. It is another animal for ten years.
The part that is genuinely hard
Most people would rather not kill anything, and the people who tried the humane-looking option split hard about whether it is.
A live-trapped mouse released nearby comes straight back — it knows the ground and your house is the best thing on it. Released far enough away that it can’t return, it is somewhere with no shelter, no food store and no route, possibly in weather it won’t survive. Released a short way off, it moves in with a neighbor. People who tried this in good faith reported all three, which is why some of them ended up arguing that catch-and-release extends suffering rather than avoiding it — while others held that released far enough away it works, and that distance is the whole variable. Nobody settled it.
That is an unpleasant thing to be told when you were trying to be kind, and it is what the people who have done it say. If you want to try anyway, go a serious distance, and not on a freezing night. A well-set snap trap kills in an instant, which is the comparison that matters — and a badly set or badly placed one can injure rather than kill, so it is worth placing carefully rather than placing many.
And if you rent
The gaps are the building’s, and the building is not yours.
In many places sealing entry points is the landlord’s repair obligation rather than a courtesy — worth checking for where you live, because it varies — which makes this a thing to report in writing rather than a thing to buy steel wool for. Put it in an email, describe where the gaps are, and keep whatever comes back. That paper is worth more than anything on this page if the problem drags on — and it means the fix happens to the wall rather than to you.
The mice are not the infestation. The holes are. The mice are just what the holes let in.
Common questions
Can't I just catch them and let them go?
You can, and this is the part people find hardest to hear. A mouse released nearby navigates back — they know the territory, and your house is the best thing in it. Released far enough away to prevent that, it is now somewhere it has no shelter, no cache and no route, in weather it may not survive; released a short distance away, it becomes your neighbor's problem instead. People who tried it in good faith reported both outcomes. Which is why some of the same people argue that catch-and-release is the option that prolongs suffering rather than the one that avoids it. If you still want to try, take them a serious distance and not on the coldest nights — and check your local rules, because releasing trapped animals is restricted in some places. The honest version is that the people who tried it did not agree about whether it works, and it is not the clear kindness it looks like.
What actually catches them?
Peanut butter, on a snap trap, and it is not close. It came up again and again — strong-smelling, sticky enough that they have to work at it, cheap. Use a smear rather than a lump. Place traps along walls rather than out in the open, because mice run edges, not rooms. And if something is repeatedly eating the bait without being caught, that is a sign to change mechanism rather than to try harder: an electric trap dealt with exactly that situation for one person here.
How do they even get in?
Through a gap far smaller than you would guess, which is why this feels mysterious. The places to look are where something passes through a wall — pipes, cables, vents, the gap under a door, the join where the wall meets the ground. The materials that hold are steel wool packed into the gap, caulk over it, or hardware cloth across anything too big for either. Expanding foam alone does not work; they chew straight through it. Nor does a plastic or wooden patch.
Full tip: https://findangel.org/tips/seal-the-gaps-the-mice-come-through · FindAngel.org — free, always.