Recently, I purchased a Pocket Positive in .32 SW Long (.32 Colt New Police). After a range trip, we noticed a hitch in the double-action pull. Being a complete newby with the Colt double action lockwork, I figured "how hard can it be?" and dove right in. I studied the action thoroughly, watched a couple of YouTube videos, and began disassembling the revolver, looking for the glitch.
I found the glitch, about 50 years of no one cleaning the revolver. I also got an opportunity to look at 1920s era gun manufacturing, and there were lots of interesting things to see. Delicate machine work that we'll never see the likes of again. It was like opening a time capsule. I didn't try to stone or file anything, simply clean and oil the innards of that revolver. After two hours, I was done, the revolver was re-assembled, and I have a new appreciation for the way a Colt revolver was assembled during the 1920s. The double-action pull is slick as snot and the little revolver seems to shoot just fine.
That doesn't mean that I want to "get under the hood" again on that little gun. My 60 year old eyes ain't like they were even 10 years ago.