I don't think 6 hours is enough time.. Generally meth will leave your system in about 2-3 days. Eating and drinking lots will help speed this process up but meth dramatically suppresses your appetite so It'll be hard for you. I know how it is.. I used to smoke lots of meth in college. Get off that stuff man. It's a life destroyer! I'm lucky I was able to quit when I did. Some of my friends weren't so lucky. They ruined their lives because of their addiction selling all their possessions and stealing from family members.. Not to mention meth will make you "lose your mind" sooner or later. Good luck.. I genuinely mean that.