If you insist on peanut butter, take a 1/2" piece of panty hose, place pb in that and make a small ball, then attach to bait pan. Rats and mice will snag the panty hose with their sharp claws or teeth. You will catch them every time.
Even better. Get some hard kernals of corn from the feed store. Rats and mice love grain. Glue the corn to the bait pan and around the pan. You will catch them easily and will not have to rebait. I use this method in my shop.
