Stripped the MS frame today and cleaned out the bottom bracket and headset cups. I used WD40 to wipe up the frame and fork, then used Scratch Doctor polish to polish the paint. The paint looks nice, though there is a little touching up to do before it's done.
I also cleaned up the handle bars and stem, polishing them with Simichrome. Simichrome is my pick for cleaning up metal parts, especially plated stuff. It's not cheap, but it does a great job. It is also worth noting that the bike makes heavy use of older, Wald parts. The bars, cranks, and stem are all marked "W" or "WALD". Manton & Smith was a small builder, so bought components from outside companies like Wald. It is likely that this was a straightforward, relatively low cost bicycle in its time.