My friend used a detox drink (the ones where you drink it a couple hours before your test) and passed after tokin' up the day prior. The drink was about $35 from a local head shop. If I was you and had access to a car i'd find out what detox drinks are at your local head shop and either ask them witch one works the best or Google them. Dont stop smoking. Dont give in and let them control your free-time just because you want them to hire you. Is your privacy worth it?