rustic vintage pewter dinner plates, Crown Castle dull silver cast metal ware

Set of four vintage 'pewter' plates (cast aluminum type material, like a lightweight Armetale). These are dinner plates (9 3/4" in diameter) marked Crown - Castle.

All have wear, spotting and tarnish - I think a good cleaning and polishing would probably help here. They're all just as found out of a mid-century vintage collection.