Chitownsmoking and shylas are exactly right. I would not take any weird substances or go buy a bunch of shit to put in your body. If you have ten days, you should be able to clean out enough to pass just fine. Working out and drinking water is your best bet. You need to get your muscles to metabolize all the THC byproducts that are stored up in your body, and then flush them out with water. Exercise a legit lot and drink a ton of water --- BUT as has been mentioned, don't drink too much the day of the test, or your piss will be so diluted that they won't get clear results, and they'll make you retake it. Also worth keeping in mind, people typically say the most metabolized THC shows up in urine the first piss you take in the day, so make sure you piss in the morning (a few times if possible) before the test. That might mean drinking some water, which is fine, but don't drink more than a few glasses or it'll be too diluted for them.
Should be doable, so definitely hit the road and beat feet, knock out some serious reps of pushups, crunches, whatever you dig. Work your muscles and get your heart rate elevated, and drink plenty of water and you should be alright.