I recently purchased a WC Ruger GP100 3" with the gray finish. Got a chance to shoot it today and it shot well. How do you get all the carbon residue of the cylinder and other parts of the exterior of the weapon? I used Gun Scrubber and it did not go well. Finally used CLP and cleaned 90% of the residue off. Must be an easier way to clean this rough Gray exterior? Any leads on what works well?