I just lay them flat on a towel coat them with vinegar and then wipe them after they've had a couple minutes for the vinegar to break it all down. Wipe them off with paper towel and good to go. If the stuff gets too crusted I do like Bill said and scrape them down a little before the vinegar treatment. Keeps them nice and clean.

PS Don't take them off while they are still hot, it burns. Hmmmm, maybe I have a lawsuit thing going since there was no warning label.