Champanier

Just before Thanksgiving, I bought two sewing machine heads (one is a 127 and I think the other is a 15-30), because the pheasant deacals looked good on the 127, the seller had the original 127 manual and the price was reasonable. Well, when we met the seller, the machines looked one step above pitiful and maybe a step below sad. Totally frozen - couldn't even raise the presser feet, let along move anything on either one. They apeared to have salt crystals in some places, along with a greenish lichen-looking something (no idea what) on the finish. I asked the seller whether they came from near salt water and he said Old Lyme, which is on Long Island Sound. He said the woman who sold them to him said she'd been using them (but clearly didn't mention that she was using them as boat anchors!)

DH and I have been working away on and off since they came home. Kept trying PB Blaster, triflow oil, scrubbing connections underneath with wire brushes ... all to no avail. Yesterday I took the handwheels off both of them, wrapped a piece of thick leather belt around the shaft and DH started working on them with a vise grip. The 15-30 freed up pretty quickly and then finally he got past one tight spot on the 127 and it worked! It's not hooked up to a treadle, threaded or anything, but with one good spin of the handwheel, it zips that little shuttle back and forth on its own and keeps going for several turns.

Here's my question (got carried away with the whole story) - can someone explain how to use the dremel to polish the plates? (Actually, the 15-30 is missing the slide plate, but I'm watching for a good vintage one.) The seller had tried to polish the slide plates on the 127 and now they have deep marks from the brush he used. On the 15-30, the small metal release knob in the wheel has most of the coating peeling off and the wheel rim looks like the finish is all gone. I have 1200 sandpaper, a dremel, jeweler's rouge, buffing cream, brass, stainless and carbon steel brushes, cloth buffers and more. On small parts, like presser feet, I have good luck with Evaporust and the 1200 sandpaper. Between Mother's and Simachrome, I can usually get things shiny if the finish is intact. I've tried before to use the dremel for metal when the finish is shot, but haven't really been happy with what I did.

Can someone tell me (or point me to instructions) what the sequence is for polishing metal once the nickel finish is beyond help? Which brush should I use first? Will any of the brushes damage the finish further? Should I go in circles or straight? At what point do I use the jeweler's rouge and buffing cream?
Thank you!

Here's a picture of the two after a little cleanup. They look better now. I forgot to mention that someone had added a motor to the 15-30 by drilling two small holes through the bed. We took it off, but it's actually kind of an interesting Franklin motor with a vertical foot pedal.

Oh, one more question - the 127 serial number starts with K. I thought I'd read that K serial numbers were made in Scotland, but now I think I'm confusing this with model numbers. Ah, well.

[ATTACH=CONFIG]501952[/ATTACH]