Disassembled my GE Arc lamp and bathed the housing in ketchup for 11 hours (mild acid in ketchup eats thru the corrosion / verdigris.  Followed up by a mild soap and water rinse, painting of all sanded cast iron parts "rubber black" semi gloss enamel and cleaning and polishing of the coroded socket and replacement of old cloth wiring.  Almost ready for illumination ....globe on order!

Wow, nice! Can you find replacement cloth wiring that matched the old? Was the old wire asbestos insulated? If it was asbestos, you'll have to find some high-temp wire (like SF-2) like we use for stage light wiring if you ever intend to light this up. If that is your plan, we can help you find the wire (I might even have some scraps of old asbestos wire, though it probably isn't in very good condition).

Glass fiber sleeve is high temp and can give the look of cloth wire. But it does not give full protection - inside it the wire's real isolation still can degrade and melt

Is it possible instead to use unisolated wire on ceramic isolation (kinda like knob and tube) in the places where the temp is high inside the fixture ?