What should be used to remove blackness or fire scale?
• Most fire scale is removed by pickling in a sodium bisulfate based solution. A common pickle pot used to hold and heat the solution is a crock pot. The pickle solution works best at about 180F or 80C. Oxides that are harder to remove, such as those generated with nickel white gold alloys, can be removed by using 5% nitric acid. Fire scale is best removed form silver alloys by using a 10% sulfuric acid solution.
