I'm trying to remove a toilet paper holder so I can paint. I've discovered that the screws that are holding the unit in place are all stripped out and won't come out of the wall. I've tried getting a pair of pliers on the head of the screw, but that hasn't worked (the head is not visible enough to get a hold of it).

Anyone have any advice on how to get stripped screws out of drywall?

Stripped Screws