They sell Toxin cleaners at certain heath Stores and Head shops. Its around $25.00 a bottle but the work pretty good.
Just dont take anything 36 hours before your test, and drink the stuff like 2 or 3 hours before your test and it lasts like 5 hours. Oh yeah, Pisss like crazy too. The stuff always worked for me. I had to take pisss tests for probation and never had dirty urine. Like I said It worked for me, I'm not guaranting any thing but the Toxin cleaners guarantee it. Double your money back if you can prove you failed the test. Good Luck Man.......