CVA Barrel Blaster is a series of solvents and rust preventatives specially formulated for black powder firearms to dissolve residue. Used to saturate dry patches for swabbing barrels or use with a parts cleaning brush to remove corrosion. Also recommended for removing mercuric primer residue. Use frequently when firing to prevent loss of accuracy. Water soluble and safe for use with natural or biodegradable patch and bullet lubricants. Handy flip-top spout for no spill cleaning. 8 fl oz. Directions: Saturate patch with solvent and work back and forth in barrel. Repeat with another saturated patch. Repeat with dry patches until metal parts and bore are dry and clean.