[ Lee Freeman wrote in 180117 MMDigest --

> Can you suggest a method to clean Olympia discs?

Olympia and Criterion discs are made of zinc, not steel.  The
corrosion is in the form of white powder which can be removed with
a natural bristle brush (floor scrubbing brush) or a brush of _very_
fine brass or steel.  Some black nylon bristled brushes work okay,
too.  If you use too coarse a brush you'll end up scratching the
softer zinc and possibly bending projections on the back.

IF the white powder is located on the logo or tune titles, there's
not much you can do to save them -- you will probably lose a little
while you're taking the powder off.  It all depends on how bad the
oxidation is.

Store the discs in a nice, dry place after they're clean and they
should stay that way.

Enjoy!

Nancy Fratti - Nancy Fratti Music Boxes
Canastota, New York
http://www.nancyfrattimusicboxes.com/