Mice in Cottage Attic Crawlspace (smells, bathroom, cabinet, remove)

[NHartphotog]

We have a summer cottage next to a salt marsh that's full of mice. We have tried sealing every entry point, and have them limited to the bathroom and attic crawlspace (which has no entry). We can hear them running overhead at night and it's just gross.

How do we get them out of the attic space that we can't access? I'll catch 3 or 4 a week in mouse traps in a certain cabinet, so we know that's where they're getting in the bathroom, but the problem continues. Poison might cause bad smells of decomposing mice. Peppermint oil might work in the bathroom, but how to keep them from running around the attic at night?

Any help would be greatly appreciated!

[Narfcake]

There's prolly a nest of them already.

Might want to consider an exterminator here ... one or two, yeah, a few traps and you're done. With that many, one really needs to remove the source.

FWIW, a hole the size of a quarter is more than sufficient for one to get through.

[harry chickpea]

Put a repeating trap in the attic. A repeater scoots them into a compartment, and their noise attracts other mice and so on.

[NHartphotog]

Thanks for the info--all sounds right.

[Ultrarunner]

Grandparents had farm cats and never had a mouse problem