My tumbler came with what appears to be a corncob medium treated
with polish (for brass gunshells). I used this on a bracelet of fine
silver, and it came out covered with a dark film. After cleaning and
retumbling–this time with Sunsheen porcelain and burnishing
soap–it is just as shiny as the other bracelets, but still darker.
It’s hard to describe the difference between this bracelet and the
others. The metal doesn’t look like fine silver anymore. Actually,
it reminds me of a chrome car bumper!
It doesn’t respond to any tarnish treatments (Flitz, lemon juice
with salt, baking soad with salt, toothpaste). Any suggestions?