Cupping is the method of applying a glass cup in which a partial
 vacuum is created over an acupoint for therapeutic purpose. There
 are many styles and techniques of cupping, all of which use suction
 in cups to draw energy, blood, and fluids to the surface; to pull toxins
 out of the body, eliminate obstructions of Qi (energy) to promote 
​circulation. The cups can be various shapes including balls or bells,
​ and may range in size from 1 to 3 inches (25 to 76 mm) for the diameter of the opening. Plastic and glass are the most common materials used to make the cups. Suction can be created using fire or mechanical devices (hand or electrical pumps). Fire cupping uses a cotton ball soaked in 70% alcohol and lighting it. The vacuum can be created with a flaming cotton ball or a mechanical suction pump. Massage oil may be applied to create a better seal as well as allowing the cups to glide over muscle groups in an act called "moving cupping". Skin marking is common after the cupping. This may be a simple red ring that disappears quickly or round bruises over the affected area that may last 3 to 5 days. Cupping is most often used for muscular pain and tightness, but can also be used to treat cellulite, colds, digestive disorders, and much more.