Does shaving your head clear out the ';chemicals'; in your hair for hair test? if not, how to clear it?

I smoked up at least 5 times in the past month and my school will test us in 2 months. What are my options? Please give scientific answers.Does shaving your head clear out the ';chemicals'; in your hair for hair test? if not, how to clear it?
by washing your hair with shampoos you are only putting in more chemicals, try not washing your hair, but only with water, than your natural oils from your hair will clean the chemicals out, next time you smoke up wear a hat or make sure the wind is blowing the other directionDoes shaving your head clear out the ';chemicals'; in your hair for hair test? if not, how to clear it?
It is impossible to get the chemicals out of your hair as they are 'in' your hair from the root, which you cannot shave off. Refuse to take the school test, they can't force you.
Yes, but they'll then just use hair from somewhere else on your body.