The original self cleaning, lead free flux specially formulated for sweat fitting work. It removes oxidation and prepares copper, lead, brass, tin, stainless steel, cast and wrought iron for the proper bonding of solder to metal assuring leak-tight joints. It makes the solder flow freely and tin perfectly. It's recommended for all soft solder work, including 95/5. Meets federal specification 0-F-506. Utility Manufacturing Soldering Flux, 0.5 lb, Paste, Composition: Ammonium Chloride, Zinc Chloride, Petroleum, Tan, Odor/Scent: Low Odor, >204 deg C Flash, Applicable Materials: Copper, Brass, Galvanized Iron, Lead, Zinc, Tin, Silver, Nickel, Mild Steel, Terne Plate and Malleable Iron