well id say your best chance is to get a cleanout kit thingy. if u dont want to do mail order, a lot of drug-related stores have them, like places that sell grateful dead shirts or like those cd stores where its mostly rock music with trippy posters on the walls. probably headshops too.
its a lot harder to do, but you can drink like a gallon of water 2 hours before your test
and just keep drinking and keep peeing, and then take a standard vitamin with B2, or B12 in it to color your piss yellow
good luck man