As far as I can tell, no matter what you do, the metabolites clear out very slowly. It seems bad to take large quantities of supplements during a "detox" phase, since many will likely drag THC around the body, as well as interfere/compete with liver metabolism, and/or kidney/intestinal function. Exercise, a moderate amount of food and water seems to be the surest bet. There are other factors you can't directly change, like your body type, but a lack of exercise and fluids is why most people don't detox quickly. It is also necessary to stop exercising prior to tests and to dilute your urine by consuming large quantities of water. This will probably get you below the 50 ng/dL level, which will stop them from sending it to a lab for mass spectrometry (often GC-MS). Depending upon their body type, chronic users can clean out (< 20 ng/dL in urine) within 10-40 days if they stick to this routine and abstain.
I don't know if cannabis is the best or healthiest drug, but I can say with about 85% confidence that drug tests for it waste more money than they save via cutting "unproductive workers".
Edited by dasheenster, 11 April 2012 - 07:09 PM.