I hate when people end up in testing situations, b/c I have to worry about tests too and it's a scary feeling. In my sit., I freaked out and went everywhere and searched everything and besides synthetic urine, the best thing you can do is drink this stuff called STRIP made by Covert Labs....It's 3x the strength of the strongest cleansing drink out there. You just chug this whole bottle and in half an hour, you're clean for 6 hours. You can buy it at any GNC for $50.00 and they usually keep it locked under the counter or some bullshit so you have to ask for it.
The bad part is that it turns your lips purple or red, depending on the flavor you choose, and the flavors sound nice but they taste like shit. Its worse than cough medicine, but u know. It's worth the security.