Q: How do I get rid of mice stains—from their body oils—on our cottage walls? —Patrice Overton, via email
A: Mouse stains? From body oils? We’d never heard of such a thing. But, turns out, it is a thing. It’s called sebum, and it’s an oily substance that rodents—and other mammals—naturally produce. It builds up on their fur, mixes with dirt, and can leave stains at entry points where mice are coming and going, or against the wall, along their favourite routes of travel. (Mice like to hug the perimeter of a room, instead of cutting across it.)
“It’s a dark brown-to-black stain,” says Bill Hughson, the owner of Pro-Wildlife Services in Lindsay, Ont., and it’s thicker and darker than the typical buildup of dust you can get along baseboards. “Once you realize what it is, it’s pretty evident.”
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Clean sebum the same way you’d clean other mouse waste, even if you can’t see evidence of it. If there’s sebum, there’s going to be urine. “Mice don’t have the ability to retain it,” says Hughson. “So they’re always urinating.” (How awkward.) Rodent urine can hold mould spores, along with any disease-causing organisms that might be in their waste. “If you just go to wipe that up, the spores are going to become airborne, and you’ll end up inhaling them,” says Hughson.
You can use any household cleaner, or even a simple 50/50 vinegar-water solution, he says. “To be safe, I recommend a full-face HEPA respirator—that’s what my guys wear. You want to protect your eyes.” If, after heavy scrubbing, you’re left with discoloured walls, consider painting using a restoration primer such as Kilz, he says. “It’s often used after fire or flood damage; it helps seal in the smell.”
But scrubbing and painting won’t fix your mouse problem. And you definitely have a mouse problem: “Once you start getting a layer of sebum, it means that your infestation rate is very high,” says Hughson. “You have to figure, how many times do mice have to cross back and forth before it starts getting greasy? The first thing that I’d be doing is taking out the population and mouse-proofing the cottage from the exterior,” he says. “Then, I’d tackle the cleanup.”
Got a question for Cottage Q&A? Send it to answers@cottagelife.com.
This article was originally published in the Early Summer 2026 issue of Cottage Life.
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