Caustic pencil

A caustic pencil (or silver nitrate stick) is a device for applying topical medication containing silver nitrate and potassium nitrate, used to chemically cauterize skin, providing hemostasis or permanently destroying unwanted tissue such as a wart, skin tag, aphthous ulcers, or over-production of granulation tissue. They are not used as a treatment for minor skin cuts, and should not to be confused with a styptic pencil.