In direct moxibustion a cone of moxa wool is placed on the skin and burned. In scarring moxibustion the cone is allowed to burn down completely, producing a blister that is encouraged to suppurate and eventually leaves a permanent scar. In non-scarring moxibustion the cone is removed as soon as the patient reports heat, leaving no mark.
Scarring moxibustion is the more powerful and the more demanding. It is used for chronic cold deficiency, for asthma and for collapse, and it requires consent, careful asepsis and follow-up of the sore. Non-scarring moxibustion is far more common in contemporary practice.