Andy's unwisely asked for my opinion on this... First off, I should stress I'm not much of an infill afficiando, so largely I'd approach it just like any other bit of rust. Viz, from the archive:
For what I call "crusty" rust use a scraper/Stanley knife blade to scrape off the worst. Then I like to use maroon webrax (or other synthetic wire wool substitute of your choice, or even the real deal if you prefer) and white spirit on the japanned areas if they're very rusty, but the grey if the japanning is largely intact. If it's totally perfect and lovely, don't touch it! Sides, sole and any other areas of bare metal which are reasonably smooth get 320 wet 'n' dry well lubricated with (guess what) white spirit. Rough bare metal areas get the maroon webrax and white spirit treatment too. For awkward corners etc use whatever combination of toothbrushes, cotton buds, bits of stick with a rag around the end or mystic chanting works for you.
Obviously japanning doesn't apply here. Yes, it's painstaking doing it all by hand, but it does avoid any unintended damage you might otherwise cause if using powered means.
As far as the wood goes, I've never seen one in the flesh, but a dark varnish sounds likely. Perhaps garnet shellac with some extra stain might do the job nicely? Probably looking at quite a few coats wiped on, but I think the finished result might be sufficient reward for the effort.
I probably have a contemporary advert or two skulling about, if you'd be interested, Andy?
Cheers, Alf
