I'm not sure when your test is, but if you have some time, purchase some at-home drug tests to test yourself. If pot is the only drug you've done, you can buy a test that just looks for THC use. I recommend getting several to be sure the results are accurate.

The three important things, the ingredients that are present in all commercial "cleansing" drinks...

- B Vitamins, to color your urine yellow.
- Creatine, Creatinine is present in human urine, so for your sample to test "un-diluted" you must supplement creating
- Water, water, water!

I've also heard aspirin helps... it definitely doesn't hurt.

Good luck!