I picked up this Cartson Pewter (Freeport Pennsylvania) Pewter charger (that’s the underplate for a dinner plate) and it had this stubborn stain on it. Pewter is metal alloy, traditionally composed of 85–99% tin and is not as reactive a metal as aluminum.
The stain survived quite a bit of washing, even some elbow grease with Bar Keeper’s Friend didn’t work for me. It is obviously not something ‘on’ the surface but damaged TO the surface. It can only be offcast from acrylic adhesive that had been left on much too long and damaged the patina.
I wanted to avoid adding any heavy scratches or creating a light spot where the stain was. So I broke out the rubbing compound, in this case I had some Simichrome metal polish at hand. Rubbing compounds are an abrasive paste, ideal for polishing jewelry and other metal items where you don’t want scratches.
In the end I did have to expend some more elbow grease on this plate, but not a lot. I just went over it repeatedly and gently and instead of focusing JUST on the damaged spot, I did the entire face of it, so the finished coloration overall would be even. Although now it is TOO shiny. It looks alarmingly new but overtime with use the shine will fade. If using it for reenacting, I would start running it through the dishwasher to get it that well worn patina back. I am quite pleased with how it turned out.