SB 2301 Heavy-Duty Rust Stain Remover is a more aggressive version of our SB 2300 Rust/Manganese Stain Remover. It is used to remove heavy rust stains that have accumulated over long periods of time. In many cases, these stains have become or are approaching the point of being a scale more so than a stain. The extensive corrosion of chain link fencing or the rusting of iron attachments to masonry structures can create heavy staining that only a product like SB 2301 can remove. This carefully selected blend of acids and surfactants has solved a long-standing problem in the restoration industry that, in the past, had been delegated to abrasive cleaning and the probability of unwanted changes in the appearance of the masonry. Note that SB 2301 may etch certain acid-sensitive masonry surfaces.