Your chances are not looking so good dude. 12 days is not alot of time but its possible, so abstain from smoking from here on out. Cardio or running will help raise your metabolism and shed thc metabolites. Metamucil is a good source of fiber and will help to clean your colon. Buy some home test kits and test your self, you will also want to read the dilution sticky at the top of the forum. Practice practice practice...