How do I pass a AT-HOME test?

My parents plan on testing me because It was part of a deal with helping me buy a car. Is there anything I could add or do to the sample that'd throw the dip stick to neg.?

Thanks for any help. Lazysmoking

I highly doubt your parents will test for adulterants, so bleach will do it. Just don't use too much, or it will smell. Adulterant tests are expensive and hard to use for the normal at-home user. The company I used to work for sold an integrated cup with the 3 basic adutlerant tests built in, but I am not aware of any retail stores that stock such a thing. If it's just a dipstick test they are not testing for adulterants.