With regard to cleaning out the innards, I tried this once, several years ago (with a stainless S&W) and it worked great:
Remove the grips. Put on gloves and eye protection, and squirt brake cleaner into all the openings you can find. Cock the hammer and spray into the gap; spray into the hole in front of the trigger, the hole the hand rises from, the firing pin hole, and of course, up through grip frame itself. Let all the gunk run out, and when it starts running clear, you're done with this phase of the operation.
With the gun utterly dry and unlubed, dryfire it, 1000 times, double action. This will hurt, but not take as long as you might think. I used several fingers, one at a time, to get the job done.
Now hose the innards down again, but this time with your favorite, non hardening aerosol gun lube (NOT WD40). Let it drain overnight, put the grips back on and you're done. (I think I used RemOil, because it was what I had on hand. There are probably better choices available now).
This particular gun benefited greatly from this treatment, and suffered no harm that I could detect. I was concerned that aerosol lube might not hold up well but it's been several years and the gun still feels great.
I suppose a blued gun might have flash rusted? Dunno if that's a real risk or not, but it's something to consider.