I picked up a 5904 yesterday, and the decocker was scratched up, like someone dropped it on concrete. I sanded out the scuffs as best as possible. I thought I could go back over it with perma blue, but it doesn't have any affect on it. I was able to use it on the slide to even out some wear marks. Do you know what I can use to re-blue or blacken the the controls?
Me and my gunsmith have long thought that the controls (if they're MIM) were made from Stainless and blackened. That would explain the fact that the cold blue has little (if any) affect on them.
I would send the pieces to ROBAR or Wilson Combat (Matt Riker) and have them coated in whatever color you want. If you go the Wilson route, tell Matt that Greg Topp sent you.
Not sure if anybody else has the work-around to get them blackened.