Buy Hoppes No.9 Nitro Solvent Cleaner Quart online at Armory Shop 45. Hoppe’s No. 9 is quite possible the worlds most recognized and utilized solvent since 1903. #9 as it is often referred to is a Gun Bore Cleaning Solvent designed to remove powder, lead, metal fouling and even rust. This quick and ultra-effective formula is safe and easy to use. Hoppe’s No. 9 is safe for use with all rifles, pistols, and shotguns.