Mr has most of the bases covered..however with smoking pot..a week to detox doesn't give you much time. THC can actually stay in the system for up to 35 days. The reason has aleady been stated. It's a fat soluble. Most head shops sell things to help you get around this.. although I wouldn't swear by them. Something else you can do is to put a pube hair or two in the cup.. or a piece of fingernail. By law they can't test that specimen because it's contaminated. That buys you a little time and you're still taking a risk because if they don't see the pubes you're screwed..it's not like you can say " But I put pubes in there so this test doesn't count" I'd say stick to the cocaine.. it only takes 3 days to detox
/sarcasm