Something we failed to mention in these posts - safety. Once you know you have a problem and commit to the hunt and eradication there are a couple of things to know. When handling dead rats, used traps, re-baiting etc wear rubber, latex or some other type of glove. Put the dead rat in a plastic bag. Also in an enclosed area like in an attic, a closet, small shed etc wear a mask. Even a dusk mask will help protect you a bit better than nothing when you are sweeping up poop and dust. You don't want to be breathing it. I'm not going to get into the diseases you could get. Just google it.