There are the type with magnets that go on their collars, but if they're not used to it, they may get them off...Raccoons are a problem for cat/dog door people here in Seattle too! My brother heard a noise late one night thought it was one of the cats coming home or leaving but they sounded loud and clumsy, so he got up to investigate and it was a large raccoon in the kitchen and began arching and growling, that scared him! Luckily one of the cats woke up and the raccoon didn't want to deal with both a human and a cat!