Tin foil is how I do them - nights that your sitting watching the TV put the tin foil on the swivels and when your ready to powder you're all set. One thing to remember is take the foil off the swivel BEFORE curing them!!!!

Reading on another board a guy puts an alligator clip over the swivel and dips them - I might try a few that way but the teeth grooves I think will still let powder in, and if you do brush tapping for a second color it would go right the seem of the clip also.
When I powder again I'll give em a try - but I just picked up my grand daughter for the month of August and we're going fishing!!!!