Yea don't get fluid on the pads. They'll be ruined. Just find something that fits in there without pads. Piece of wood, plastic, Lego block....something.
http://www.pinkbike.com/news/tech-tuesday-bleeding-avid-brakes-2010.html
http://www.pinkbike.com/news/tech-tuesday-bleeding-avid-brakes-2010.html