if you rarely smoke, you'll be clean in 3-4 days... if you are a regular then things might be a bit trickier...
DON'T bother with any of the kits... the places that test will test for any adulterants and report that.
the kits that don't use adulterants are just kits that have creatine and B complex vits in them. + they tell you to drink shitloads of water.
SO, to save yourself a few $$$ just keep drinking shitloads of water and taking creatine and Bcomplex vits.
creatine b/c they test the creatinine levels in your urine to see if they are in the normal range (if not then the conclude that you've tried to dilute the sample)
B-comples vits b/c they test the color of the urine and if its not dark enough they'll conclude that you've tried to dilute the sample.
SO, as long as the color/temperature/creatine levels are "normal" and they detect no adultarants in the sample you can dilute as much as you want simply by drinking TONS of water.
no worries