In the attic, in the basement- Use MOTHBALLS, very effective. just spread them around
Are these the white/yellow mothballs? and will they keep out squirrels and birds from the attic?
I just used mothballs too and it seems to have helped
also Oil of Pepperment (for some reason the small critters hate it, especially mice)
I stuffed mothballs into every crack and crevice I could find in the attic and basement- be sure to check your house outside for entrance holes, and also on the ledge formed by the top of the concrete house footer and in the rafters and vent holes.
I waited outside to watch once because I had no clue how they were getting in- they were crawling through a hole I never would have dreamed possible for them to fit through