College students are by far the filthiest, followed by old fashioned drunks, then Asian refugees, then Mexican nationals. I rennovated apartments after them all, and that's my observation. Hippies are usually cluttered and unmaintained, but not filthy. Although minorities tend to slaughter animals in the kitchen, they've had enough experience to get the stinkiest parts out before they rot. Students have no such forsight, nor do they feel like they 'owe' it to the landlord to clean up after themselves because they (or mommy) has paid a deposit. Drunks have a 'puke and forget it' attitude, along with a 'let the piss dry into the rug' philosophy. 30 years of this shit has left me with a bit of working knowledge.