Hi there, I was watching sky fall the other day and the villain was talking about how to get rid of rats or at least get then to eat each other instead of your citrus and other food you store in the attic. He says something along the lines of digging a hole with bait in it…maybe a piece of food rats desire hung from a string across the hole but inside the hole while out of the rats reach. the rats will be drawn into the hole. the food is out of reach and so they will eventually begin to eat each other. For some reason he releases the last 2 survivors, maybe so they go out eating other rats I dunno. Anyways hope this helps.