Try using red rouge on a buffing wheel. If you don't have a polishing unit, just slip a 6 inch cloth or felt wheel on your bench grinder. I like the wheels that are 3/4 to 1 inch wide. After going over the gun with the red rouge, give it a good cleaning and then go to the Flitz Metal Polish on a clean wheel and go over it again. Always keep your wheels separated, I keep mine in a plastic zip lock bag. One for every type of polish I use and always clean the gun and polishing unit before putting a new wheel on and going to the next step.
If you use a polishing unit or bench grinder always keep the gun moving on the wheel and be cautious of keeping it on small pieces for to long, they get hot and you may end up with blisters on the fingers. Another tip, I always tear the gun down to smallest point and polish each part individually.
