Put down the joint for a couple of days until your test and start drinking alot of water now exercise might help to. I had took take a test a couple months ago for my new job and i smoked 2 days before so I scored some piss from a friend which i used, but a 2 days later I go into work to drop off working papers and they tell me that they lost my sample and I would have to take it again on the spot( i was scared shitless because i had nothing to use) so i take the test and put alittle water into the cup thinking that it might cause the test to be dilluted. A week later they call me back and ask me when I could start. It was a crazy

If you want some more info on testing read this thread by doctor. G he's wise beyond my years
http://boards.cannabis.com/showthread.php?t=62082