From various videos I see that most people apply a finish while the item is on the lathe. Yesterday I was watching a DVD (Bat Houses by David Best) and he was using a painters brush to apply lacquer. Although he covered up the ways with a paper towel it looked like he got the lacquer on the chuck jaws. Would a finish getting on chuck jaws cause problems? I am wondering about finish buildup not allowing the jaws to expand correctly into a recess.