Mountainfarmer, I believe mothballs are highly toxic. Not something you want around your plants. I've used BT and smoked bud from plants that were sprayed with BT - and from some that were not. I can't tell any difference. And yes, Veggiegardner explains the benefits of rinsing your plants down prior to harvest, a few pages back I believe. In any event, BT should dissipate and be gone from your bud as a result of being exposed to the outdoor elements: wind, air, sun, etc. I'd stop using it around 2 weeks prior to harvest. Unless conditions demand you spray again 1 week prior to harvest.
Oh, that link you attached doesn't work. Best of luck!