Long time ago, I picked up an old revolver; Smith & Wesson M&P in .38S&W. Needed some work, which eventually got done, and shoots pretty well, but the finish was fairly bad; worn in places, in places looked like something had splashed on it and taken the bluing off. So a while back I decided to refinish it.

This was the good side, the other was much worse.
Cleaning the surface was pretty straightforward, as there was no pitting to remove: 220-grit wet/dry paper, used wet, to clean it up. With a piece of wood as a backer to keep the flat surfaces flat. Then borrowed friends’ bead-blasting cabinet to go over everything, giving a nice, even, clean surface. At which point a couple of things happened:
The weather turned bad, and this being something that has to be done outside(me not having a vapor cabinet or anything) it had to wait, and
I’d decided to parkerize it, and realized I didn’t have anything to plug the barrel and chambers with.
That last is important. If you parkerize the barrel without it being plugged, sure, a few rounds fired will strip the parked surface off, but the process etches the metal slightly, which means it’ll foul worse than before. The chambers, well, you don’t want anything on the chamber walls, so you have to clean the parking out and polish the walls a bit; easier to keep the stuff off in the first place. So the pieces were oiled and boxed until later.
You
can use wood, I used some Delrin rod: turn an end into a nice cone on the belt sander, cut that off, do another until I had fourteen plugs, two for each chamber and the bore. While the parking solution was heating I tapped the plugs into place, then washed all the parts to be treated with Dawn soap and water and a brush, rinsed them thoroughly and hung them on stainless steel wires.
I’ll note that when I parkerized the Sistema, I used a gallon jar in a big can as a double-boiler, but the jar wasn’t long enough for this barreled frame. Friend gunsmith had an idea and I checked a kitchen supply shop and found trays for steam tables, stainless and in various sizes, and found one that was perfect size for this.
As I wrote before, the process is simple: have the solution up to temperature, take the prepared and degreased pieces and hang them in it. The solution will start bubbling around them, when it stops the process is done; take them out, hang to dry and then grease or oil. Came out pretty good.

The grips are a pair I made so it'd be more like original condition. And yes, my photography has improved.
I discovered something that may be handy to know if you try this: I found two spots on the frame that, best as I can tell, I somehow missed getting all the oil of, a neat spot on the bottom of the trigger guard and one on the left side, that didn’t park. Soon as it was cool enough to handle I took it to the sink with some #0000 steel wool. Wet the frame, put some soap on the wool and rubbed both areas. The wool took some of the parking off the surrounding area, no surprise, then I rinsed it well and put it back in the solution, and it worked; nice, even finish all over.
I also discovered just how slippery wet Delrin rod is, pulling the damned plugs out took some doing as the pliers kept slipping off. And they worked perfectly, not a speck inside the bore or chambers.