How to get rid of mice

Mice. They’re cute. They have important roles in animated movies. They lead us to reflect on the differences between urban and rural life. All that said, we don’t want actual mice in our houses. I’m fighting an ongoing battle against mice and I want to share what I’ve learned so far.

The first line of defense is the mousetrap. If your idea of mousetraps comes from cartoons (or from the 1980s), you might picture a miniature wooden platform with a metal hinge and a piece of cheese as bait.

All of that is wrong. These days we have traps that are much easier to work with. I use one called Better Mousetrap. To remove the mouse, you simply squeeze the spring-loaded jaws open. It’s the same process to reset the trap. And if you accidentally snap it on your finger, it doesn’t hurt that much.

Also, don’t use cheese. Peanut butter is the bait of choice.

Mousetraps, though, are an admission of failure. If you’re putting them out, you’re already losing. The goal is to keep the mice out of the house in the first place. Easier said than done! Depending on which source you read, the critters can fit through an opening the size of a pencil, or a dime, or half an inch. Whatever the exact size, that’s a pretty small hole.

So the most important thing is to find the holes. To do that, you can’t just look from your giant human vantage point — you need to take a mouse-eye view. You could try to see things like a mouse by laying on the ground, but it’s more practical to use an inspection mirror. This handy tool features an angled handle that allows visibility into hard-to-reach spots, sort of like a larger version of the mirror that the dentist has to check your teeth for cavities. Hold it near the ground pointed up to look underneath siding, trim, and other potential entry points.

If you find an opening, you have a few options for closing it. (Keep in mind that a hole might also lead to other issues, such as water damage. We’re only discussing mice here.) Steel wool is one of the quickest and easiest. Mice don’t like to chew through the fine threads of steel so they will leave it alone.

The problem with steel wool is that it tends to rust. An alternative is a copper scrubbing pad, which you can cut to size with tin snips.

After these scratchy metals, the second option is foam sealant. This product comes out of a can looking kind of like shaving cream, then expands and hardens as it cures (some varieties are non-expanding). The foam has the advantage of easily filling any shape of crack. After it cures, you can cut off the excess and even paint it.

The sealant is supposed to be reusable, in the sense that you can spray one crack today and do another one a few days or weeks later. However, I’ve found that the hardened foam usually clogs the delivery mechanism and makes the can a one-time-use product.

The more significant disadvantage of these sealants is that mice can eventually chew through the foam. Some people advise filling holes with steel wool and then using spray foam, so that the steel wool is embedded in the foam. And some kinds of sealant are supposed to have a bitter taste to deter mice, but this feature seems to get mixed reviews.

In general, the best solution is a mechanical barrier: caulk for small cracks, wood or metal for larger openings. This is not a time to do your most beautiful work. You are likely fixing a spot that no one will see, so practical effectiveness is usually good enough. Maybe hardware cloth, or a small piece of scrap wood. With a little work you can keep the wildlife outside where it belongs.

If you have a tip for keeping mice out, please share it below!