I've been going through a desk drawer and discovered a set of color filters for b&w film that my father must have used with his leica lenses. They're tiny and I there an attachment to screw on the lens that you put the filter in and a ring to screw the filter holder in place on the attachment. I'm sure some of you know what I'm trying to describe here. anyway they seem to be Kodak filters, not Leitz or Tiffen or such. And they're not in terrible condition although the nice leather case they lived in is so brittle that when I tried to open it pieces of leather snapped right off and I had to pry the snaps open with a knife blade. Are they worth anything at all?