there are a couple of ways. i know my boyfriend did it with this meathod and was clean the day after we smoked! but remember. it is not going to be fun. what you need to do is get about 5 shot glasses worth of vinegar. some vitamin b 12 and a whole lot of water!. every hour for about 5 hours, you will have to take a shot of vinegar and then drink a lot of water until you can not taste the vinegar any more. and take about 3 pills of vitamin b12 in that day. the vinegar does a "quick flush" and the water speeds the process even more. the b12 boostes your metabolism to push out anything..... do this the day before your test.