I tried the bucket, It froze and they ate all the peanut butter. I also tried the tractor exhaust thing. Will never know until the place starts to stink of dead mice. Mice won't chew on closed cell foam, So I finally went around my camp and foamed every crack I thought a mouse could crawl through. Then I set my traps as a backup. Been a year without mice.
^^ this is pretty much what I did...I just repaired any spots that they could enter the building, and I've been mouse-free for several months. They can climb straight up walls (I didn't know that until I saw one do it right in front of me), so make sure to seal areas up higher that they might be entering.