i have been on probation/ parole for about 10 years now and the best method i have found is good old fashioned H2O. the only time i have EVER failed was when i bought one of those 50 dollar flush drinks. i would drink around a gallon of water an hour before i reported. piss six or seven times and pass every time. after you drink that much water you should be pissing every 15 minutes like clock work. after you have several crystal clear urines you should be good. NOW THIS ONLY WORKS FOR THC!!!! cocaine or opiates barbituates.... doesnt work as well from the info i have gathered. but for thc i can tell you it works every time....