As long as we are on the topic of methods to deal with mice. I learned from the pros that you do not want to use a method that involves bait like the snap traps and poison. They actually just attract the mice from all over and even though you may kill the one that ventures into the trap or eats the bait, more will follow, as they follow scents left by those that came before them.
The best devices to use are the ones that just trap the animal and use no attractant. I have seen small one animal traps in hardware stores and even Walmart and have seen the multi animal traps in farm and garden supply catalogs.
Good luck trying to stop these buggers. They can fit through holes with a diameter as small as a dime. Spray foam is your best bet to seal them off from getting inside.
After 4 years of dealing with them, I think I finally sealed them off this autumn. Next time I will listen to my wife when we are building and she says: "We should seal that up, a mouse can get through there."!
-John