Originally Posted by Proofide

As you suggest, the plating is toast. Assuming that this bike will have rim brakes of some type, no matter what you do, I doubt if you'll ever get a satisfactory braking surface. If it were badly pitted, it would wear your pads very rapidly. Is there any compelling reason to retain these actual rims? If the hubs are of particular quality or interest (Dynohub or Sturmey Archer gears, for example), you could have the wheels rebuilt around them with stainless spokes (always a good idea) and either steel rims for authenticity, or aluminum for improved braking. If you do wish to keep these rims, good old Naval Jelly might be worth a try in the first instance. You could then use wet and dry abrasive paper on the rims with warm soapy water, to see what sort of a surface remains under the plating.