I have a Progress Vulfix Ltd/Sheffield Mint pewter shave mug that I bought some time ago for $50 during a weak AD moment. It's a beautiful mug and comfortable to use, although I prefer my roomier Col. Conk ceramic mug. The problem with the pewter is that it leaches metal, a gray discoloration, into the soap from where it contacts the bottom of the mug. I certainly don't want this on my face or in my brushes so I stopped using the mug. Has anyone else had this experience?