When I was in college, four of us shared a suite. One guy had a little different hygiene standards than the rest of us. When he got a little too ripe, we dropped some subtle hints: leaving a map to the shower on his desk, telling him not to move so much because stink molecules were falling off, turning on the shower and picking out a change of clothes from his drawers, etc.
This roommate also had his girlfriend over and she would try to spend the night. This one evening my son was in the room working on his laptop. She began to take off her top and my son said, "Seriously, you are really going to do this to me while I am sitting right here?" Since it was after hours there was a knock at the door because the RA had an inkling she hadn't left yet. Well, she hides in the closet. The RA opens the door and asks if there were any visitors in the room. And my son motions with his eyes to look in the closet. The two lovebirds got written up.
My son got out of that school as soon as he could and after that he always checked his roommate out before signing up with them.