They sell shampoos at head shops and tobacco shops. Ask them and they'll show you, BUT some work and some don't. A good shampoo the store or the manufacturer will gaurentee. Also when I did mine, after you wash your hair with the special shampoo, DO NOT: use your brush,or hair ties(they still have the oils and will only spread them all over your hair again.) Your clothes must be freshly washed and dryed, watch you car seats don't let your hair touch them(like if you smoked pot in your car) So pretty much after you wash your hair don't let your hair touch ANYTHING. Also the shampoos usually have a small window of time that they'll work for,1-3hours or so. Make sure you ask LOTS of questions when purchasing.
