Unexpected Visitors

Jon and I have discovered that we have mice in our house. They started out just hanging out in the laundry room so we set traps and plugged the hole where they were getting in from and they have since left that room. Now however they have decided to occupy the kitchen drawers. Gross! I had to take everything out of the drawers, throw baking goods away, and wash every dish towel that I own. What is their deal? Don't they know they need to be invited formally before entering a persons home. So for now Jon will just keep setting traps and disposing of the bodies until we know for sure they have vacated our property. If they ever go past the kitchen though there will be a full out war because I don't want these mice running around wherever they please.