Activated charcoal is known to act as a magnet which attracts and then removes impurities from your hair and scalp. Dandruff, redness, oily and itchy scalps may be relieved with activated charcoal. You can use it as a scalp treatment before you shampoo or can be mixed in with your shampoo. The activated charcoal will work on your scalp the way it does on your skin and hair: pulling out toxins and purifying.