ive heard that the drops inserted directly into the cup work better than any internal cleansers, which are unreliable at best. your hypothetical friend would need to drink TONS of water AND not ingest anything questionable (that includes both thc containing stuff, the other obvious things, and un-rx pharmies- remember long 1/2 lives of fat soluble thc) the reason being, this will most likely result in an "inconclusive" result, which means he will most likely be asked to repeat the screen. watch the pockets- they usually make you empty them and may even do a more thorough check of your person (remove socks, etc). best of luck to your hypo. friend, and remember: GALLONS of h2o.
