I use metamucil and eat light foods(chicken, fish, pork).. The metamucil helps to excrete thc through your colon. But any high fiber foods you can find will work. You'll want to do this till about 2-3 days before the test then go into hibernation(be as lazy as possible, eat fatty foods and as much red meat as you can.) Your basically trying to stop your body from excreting any more thc.