How did you go about using the cleansing shampoo for your hair drug test and what kind?

I have used All Clear and Nutregena and Extreme.How did you go about using the cleansing shampoo for your hair drug test and what kind?
Hair gets drugs in it from the follicle where the hair is growing from, so it ends up in the hair shaft itself. Any and all cleaning products will only clean the outside surface of the hair shaft and will have no effect on the inside of the hair shaft thus having no effect on the drug test.