depends on the test, but i dont think those pills and stuff really work anyways. THC sticks to your fat so there's really no way to CLEAN your system out. if it's just a shitty strip test don't smoke for a week, dilute, and you'll be fine. If it's a lab test, do the same thing and take a large dose of b-12 so your piss comes out yellow. It might be considered an "adultered sample" but you'll definately be clean. They might ask you to retest but at least you're getting more time to clean out!