Blackheads are hair follicles where keratin has mixed with sebum, oil produced from the skin's sebaceous glands . When the pore gets blocked and is open to the air, the sebum oxidizes and becomes black, note that this is not due to poor hygiene. To deal with blackheads, you can use a mask that absorbs oils and minimizes their appearance. Calcium carbonate and natural clays are great at this, french green clay is particularly popular amongst acne sufferers. Furthermore, retinol containing can reduce your skin's oil production, and reduce the speed of blackhead formation . Cleansing your skin regularly could also reduce blackhead buildup, and is known to reduce the chance of acne breakouts .