You can buy one of these at Home Depot, Lowe's, or the like for about $25. I know they like nuts (for bait.) If you can find out where they nest up there, put the trap as near to the nest as you can w/o disturbing it or as near to the exit/entrance hole as possible. If you don't want to buy a trap, the SPCA rents them. But if it's like the SPCA in my area, you'll have to wait 6 weeks for a trap! Also, there are professional exterminators too.