Very visual trick. This could almost be impromptu and ready to go, if you have the right size
napkin. I find Starbucks napkins are perfect for this as it is an adequate size/length. Good
instruction. I find as I practise with this more, I can figure out other ways to start or end clean.
At least a couple of good ways are taught to end clean and ditch the gimmick. If spectator gives you
their card, I find it easy to start and end clean. Otherwise, if you just use your own card, I find
it not as easy to start clean, as my card really can not be examined. It could, but it's risky.
Overall, as long as you can end clean with everything examinable, in the end, it works for me. :)