well i can give you some tips (aside from buying detox agents that are specifially designed to make you pass your test) i can't guarantee any will work 100% just myths i've picked up (some aren't quite so myths) first drink alot of water all the time... and the few days before your piss test, especially make sure you drink atleast 1 gal a day, and you are going to have to work out.. hard.. i'm pretty sure i heard that the more you sweat the faster it's getting out of your system can't really hurt to try.. night before the pisstest take 3-4 AZO cranberry pills (they're originally for urinary tract infections and stuff but i've heard more rumors about these things cleaning piss then any other conventional home method) or my personal favorite... soak your dick in bleach.. may not clean your system out.. but when you whip it out make sure they see it and say.. "man.. i knew i shoulda tested that girl before i fucked her" i betcha they won't even wanna touch the cup lol....

or, you could always just buy someone's clean piss... you could also quit for a few months... some places around here say you have to agree to an inital test, then you are subject to more testing, but in reality they give you like 2-3 tests and if you come up perfectly clean, and don't act like a dope-fiend on your job then they don't test you anymore...