Okay...this is going to gross you guys right out, but it is really important to know. Mice don't have bladders...they leave a constant trail of urine behind everywhere they go...yes, think silverware drawers...mine used to be full of them. Ugh!
I used to buy those live trap boxes that trap a whole bunch of them at a time and then flush them down the toilet. You put them against a wall in an area they frequent (hint, they follow thier old urine trails) I used peanut butter inside mine.