Sparex Pickling Compound 10oz. Sparex is an easy to use, long lasting solution for removing Fire Scale from Gold, Silver, and Copper, after Soldering. Sparex is a non-flammable granular compound, and mixes with water. Mix about 1 Teaspoon of Sparex per 1 cup of water, preferably in a crock pot or our SO584 Hot Pot. Heat to about 180* and it's ready to work. Use Copper Tongs to remove items from the Pot. Size: 10 ounces Why do I need this item? Fire Scale is a hard to remove surface coating that occurs when Metal is heated from Soldering. Sparex removes Fire Scale, without damaging the item, saving you valuable time spent polishing!