This section is from the book "Materia Medica And Therapeutics Inorganic Substances", by Charles D. F. Phillips. Also available from Amazon: Materia medica and therapeutics.
Superficial naevi may be safely destroyed by painting with strong nitric acid; Mr. T. Holmes speaks highly of this method. Due precaution should be taken to protect the sound skin, and an alkaline lotion should be used afterward. If the affected part be extensive, a portion only should be treated at one time, the caustic being applied about every second day, until its full effect be produced (Lancet, ii., 1866, and 1867). For small naevi on the face, I can recommend puncture with a needle dipped in the acid: it is safe, effective, and leaves comparatively little scar.