hi mate i my self don,t use sand paper on the metal blueing you can get the blueing remover off ebay , you will scratch the metal work on the gun you can bye the kit off ebay have a look mate thats what i use and the name,s PERMA BLUE AND THE TRU-OIL GUN STOCK FINISH KIT before you use sand paper on the metal work you can bye the six for around £23.00 pounds good luck with the finish matey