3-4 hrs before the test, start pounding water (i'm talking like 2+ liters).. in about an hour you'll piss, then in like a half hr, etc.. each time you piss the urine will be clearer and clearer, so by the time you take that final piss for the test, it'll be very watered down and nothing will show up (in my experience).. they could talk shit cuz it's so clear, but just say you drank alot of water to make sure you'd be able to go.. should work fine