I'm talking about the kind that after you have used oil and 0000 steel wool and even a brass brush, there is still raised (200 grit'ish) sandpaper like patches.
Can it be scraped off? I'd like to do the work myself. It ain't got to be perfect, it's just gotta be better than it is.
This is on an S&W revolver side plate, Along with other exterior parts of the gun.

I would try scraping it with copper. Use either a one cent coin dated 1981 or earlier, or a piece cut (sawn) from a copper sheet found at a good hardware store or a place that specializes in hobbies.

In my experience scraping with copper removes the rust pretty well without damaging the steel. It will, of course, have no effect on any pitting.

After what you have already done, what is left are probably pits that won't scrape off. I'm afraid that the damage is permanent.

If it's "raised" it isn't pitting. The pitting is under the stuff you'll scrape off. The copper penny scraper trick has worked for me. Put a couple of drops of oil on the rusted area first.

I've also seen a flattened brass cartridge case used. The copper is softer and less likely to damage adjacent blued surfaces.

I tried a flattened brass case and it worked great. I'll try a pre'81 penny too.

Thank you very much for the direction.

If there are rust pits, then it's a good idea to use dilute phosphoric acid to convert the iron oxide (rust) into iron phosphate. Stopping the rust below the surface.

You can get Jasco Metal prep or metal etch at Home Depot etc.