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.
Preparations of potash (soft soap, etc.) are indirectly useful in parasitic disorders by softening the epidermis and removing secretion, and thus allowing the more direct contact of sulphur or similar remedies, hence the carbonate is a frequent ingredient in pomades for scabies. The sulphocyanide of potassium is a direct parasiticide, and has been commended by Dr. Gee in ringworm (1/2 oz. in 8 oz. of water).