It's important not to confuse the ammonia based copper solvents like Sweets, Butch's, etc with the copper solvents like Boretech and ProShot which remove copper with the use of a Chelating agent(compounds that chemically bond with the copper enabling easy removal). The ammonia based solvents are far more corrosive to the barrel with prolonged exposure then the chelate based solvents, Bore-tech, also contains lubricants that allow prolonged exposure without damage to the barrel. I still prefer to wipe the Boretech out with a few patches and apply a good lubricant, especially if the firearm will not be used for s while. Having used the Boretech products extensively in several rifles for over 10 years with exvellent results,