Trusted Acid Cleaner for Jewelry, Soldering, and Metal Finishing Megacast Sparexno. 2 is a professional-grade granular acid compound used to clean and pickle non-ferrous metals like gold, silver, brass, and copper after heating or soldering. This 10 oz bag is perfect for small workshops, DIY jewelers, and hobbyists looking for a safe and reliable alternative to traditional sulfuric acid. Simply mix with warm water to create a powerful pickle solution that removes oxidation, scale, and flux residue — leaving your pieces clean, bright, and ready for finishing. Sparexno is non-flammable, non-explosive, and made in the USA.