I ordered a custom box and in the meantime picked up a primo double box cutter for $9 just to hammer on and learn on and entertain me in the meantime. After watching several videos it's clear that just like with a pot, you never want to touch the friction surfaces to your skin to avoid oil, sweat, etc. Then in the same videos the guy is cutting using his thumb as a stopper and resting it directly on the soundboard (edge of box) where sound is created during a yelp.