It's clean now! The only thing that's been affected permanently is the hammer, there are a few small pit holes on it from where there was actually rust, but it's barely noticeable now that it's cleaned up. Here's the story.
I took it to a gunshop today whose owner is a big Colt revolver fan. Before I could say anything, he took a dab of Simichrome polish and put it on a nondescript part of the frame. It removed the cloudiness, and then he tried it on the cylinder. It removed it there as well, and every other place on the revolver! I have to go over it again once more because I didn't want to spend an hour in the shop for every nook and cranny, but it took off all of the major markings and now it looks like a new revolver. I know, it was a risk, but I didn't think I had anything to lose as it was a mild polish.
One other interesting thing, the S/N is pencilled inside the grips, but the last number is off by one digit. Strange!