Any pore that becomes clogged with oil, dead skin cells, and bacteria is known as a comedo. Blackheads are also known as open comedones, which means the pore is open at the surface of the skin. It’s a myth that the color of blackheads is caused by dirt. Blackheads form when oil and debris in a pore darken upon exposure to oxygen in the air. Blackheads are most commonly found where oil glands are most active, typically on and around the nose and outward to the cheeks. Exfoliating acne products and ingredients like salicylic acid can help keep the pores clear of clogging debris, improve the look of existing blackheads, and help prevent new blemishes from forming.