Always keep the work going "with the grain"--make sure that if the wheel grabs the part and rips it out of your hand, nothing can get hung up as it leaves, and make sure it goes away from you if it leaves. Always use the "bottom" side of the wheel's rotation, and don't give the wheel any edges to grab on to. Also, hold the piece in such a way as to be sure you won't get hurt if it does fly. George once had a piece hit him twice before it was all over--the piece hit him in the head, bounced back into the wheel, was thrown into his knee, bounced back into the wheel again and was finally thrown across the room. He limped for a week, got several stitches in his head, and considers himself lucky that was all.