I have a pair of antique globs in my head that have trued black when light is off from a bad water heater. Color comes through when light is on. Anyone know what I can use to clean them. Had an old timer tell me to get some battery acid and soak them. I have tried several paint and varnish removers, nothing is working. The brass polished right up from being black. The wife has let me know if I had fixed the water heater the globs 0would be ok still.