Cupping is often used for ailments such as asthma, congestion from colds or influenza, backaches, and various other musculoskeletal aches or pains. The method of cupping involves the application of glass cups to the surface of the skin. The cups are applied to the skin by taking the oxygen out of the cup by the use of an ignited flame. The cup is held above the skin near the area where it will be applied. A cotton ball is then lit, put inside the cup and withdrawn quickly before placing on the skin. This then creates a vacuum suction on the skin due to the rapid decrease of oxygen. The cup or cups are usually left on the skin for 3-5 minutes. Cupping will leave a reddish purple mark on the skin that will disappear after about three to seven days.