I just wanted to report that I got very good results using bluing paste to eliminate holster finish ware on one of my guns. I liked the results so much that I ended up doing the entire slide and the several areas on the frame.
The pistol has a mat blue/black finish. I did this while sitting on my couch watching a movie. After degreasing the gun with some alcohol, I applied the blue paste over the areas I wanted to blue, waited about 1-2 minutes, wiped it off, brushed it out with some fine steel wool, and repeated 2-3 more times. I didn't just wipe on the paste and let it sit - I continued to work it into the metal with a Q-tip until it started to dry.
Going into this, I had read all kinds of things about not using cold blue, streaking problems, coloration and color match problems, so I had pretty low expectations. This particular gun did not have any high gloss royal blue finish - just mat black. It also was in great shape, except for holster ware. I figured I didn't have much to lose. Much to my surprise, the gun looks like new. The bluing matches perfectly. No streaking, no blotchiness, covered all of the worn bright spots and the finish looks factory. I'm no expert, but I wouldn't be able to tell that it had a cold-blue touch-up.
I'll have to see how it wares, but during the process, I tested some areas by more aggressively buffing with the steel wool, and the blue did not come off at all.
I don't know if I'd try this on a Colt Python.........or would I???