I recently purchased a very nice antique sporran with a silver cantle and silver balls on the tassles. These are probably plated only, I am guessing. The fur face is a very light color, and some of the tarnish from the balls has left dark streaks on it. How does one clean tarnish from fur without damaging the fur and leather bits? I'm not sure what kind of fur, but I'm guessing it may be seal, if that matters.