Disassemble completely and other than the springs, put it in a bath of Evapo Rust, it will take it down to bare metal, but will not harm the base steel at all. It is non toxic and safe to handle with bare hands. Then you can take off the barrel and reblue (recommend rust blue like Eddie Janis of Peacemaker Specialists) send the hammer, loading gate and frame out for case coloring, the real thing and have the screws, base pin and small parts nitre blued. The gun will look period correct.