seriously.... i have doen this a few times... drink so much water before the test that you are pissin straight water (clear, no yellow at all).... depending on who is doin the testing and how important it is to them to fuck you over, they will either a.)call it a clean test b.) make you take the test over when the results come back (which will at least buy you a little more time & that might be all you need) or c.) call it a failed test and say you fucked with it on purpose, to which you can reply by sayin you had some really spicy/salty food and just happened to drink a lot of water or some shit and play all stupid and innocent... and hopefull get to re-take with clean by the time all this goes down...
they WILL NOT find thc in your piss if you do this right, but they can tell you have a lot of water in your piss (creatinin levels or some shit )
and take your stupid ass to the gym, sweat your fuckin bag off and drink drink drink constanly... water, cran juice whatever (no sugary soda shit)
p.s. ( be careful with the timing cuz i've sat waiting to take a piss for 45 mins in some serious pain cuz i had like 2 liters of water in my bladder that wanted to come out real bad and the shit does not feel good at all )