I wouldn't do that, you might hurt yourself, and I doubt it would work. I have taken many drug tests and passed having taking drugs such as benzos, herion, marijuana, and amphetamines the night before the test. Any one can pass a drug test on anyone of these drugs(marijuana only if it is not used more than twice a week). All you have to do is drink water until you are going to puke, then drink more water, and then some more. You should start about 4-5 hours before your test and continuously drink water. If you can not have diluted urine, then take some vitamine B12 1.5 hours before you have to go. You should urinate at least 15 time before your test.
For the past year I have been getting 2-3 drug tests a week and have not failed one of them. I take them for probation and for some reason they don't care about diluted urine, so I piss clear every time.
I have cut back alot on my drug use because it became such a pain in the ass to pass a test and it would waste my whole day prepairing for the test; but it can deffinitly be done. I don't smoke marijuana anymore because from what I read it has the longest half-life; but I did pass after smoking marijuana about a dozen times. If there's a will there's a way.