Sounds like it's time to start playing some practical jokes these clowns. Get the book "Make em Pay" by George Hayduke. Funny ass stuff. It's a little old school but it's got some real good tips. You can read it here:

http://www.scribd.com/doc/4542452/Ha...ster-Trickster

My Dad's done quite a few of them to renters. Some of it's illegal but all in good fun :rick: