the best way to pass a piss test is to flush before the test, just drink water by the gallon until your piss is clear, if its for probation they will say its diluted but you can cover that up by taking creatine, thats what they measure in the piss to see if you have been flushing, when you do the water flush it wont clear your system completly but it will dilute your piss so much that they cant tell whats in it, as far as the masking stuff goes i had the lab call me and say i was dirty and that i used tommy chongs so i lost faith in that stuff, but with water i survived 13 months of parole with just water, and if clear piss freaks you out eat 5-6 centrum vitamins and it willl give it some color