Bob Fitterman asked about removing rust from music box discs.  I have
used electrolysis to remove rust from old tools, clock parts, and other
steel and iron articles.  The information came originally from the Old
Tools mail list, and is written up in detail by Ted Kinsey at:
http://www.cs.cmu.edu/~alf/en/electrolysis.txt

If anyone doesn't have web access, I'll be happy to mail them the text
of the article.

The method is simple and safe; it uses washing soda (sodium carbonate)
and a 12 volt battery charger, and takes anywhere from 2 minutes to 45
minutes, depending on the depth of the rust.  It's important to wash
the residue off the object immediately after removing from the
solution, then quickly dry and protect the surface - a thin coat of
paste wax will prevent further rusting.

The electrolytic treatment is a major improvement over wire brushing,
Naval Jelly, etc.  Try it!

Bill Burns
Long Island   NY   USA