I have some really old but strong casters which were once cleanly galvanized but which have corroded through the zinc in many places. They appear basically sound, though. I am contemplating heating a strong solution of lye, then shutting off the heat (no open flame!) and putting in the casters (sans wheel, of course) with the goal being to remove all dirt, oil, grease, and, of course, zinc. Then I'd rinse in boiling water after which they should self-dry quickly. Then I could brush off any rust and prime the tops and then weld them to a plate, after which I'd paint the plate and the casters all together, then reinstall the wheels.
I believe that the lye will dissolve the zinc, releasing hydrogen. I'd do this outside, in free air, with no open flames nearby.
Anyone have any comments? Experience?
GWE