For Philip Jamison's question:

   Open Mercury Switches ... Get rid of them. Why take the risk? I know
   that in the 40's mercury was regarded as a toy. Kids played with
   mercury rubbing it on copper coins to make them look silver ... or
   just watching the stuff roll around in little balls on a flat
   surface.  However, in industrial situations by the 60's cleanup
   teams came with protective suits to clean up mercury spills. Is the
   vapour toxic. You can be certain that it is. If you have a music
   machine that uses open mercury switches, replace them.

For Lary Toto's methylene chloride reference:

   Same story as above ...  ethylene chloride was used openly as an
   industrial cleaner for electronic parts prior to the 70's. The stuff
   is now banned from all cleaning operations. It kills the liver and
   is a carcinogen. If you must use methylene chloride to strip
   finishes, wear a respirator or a special face mask designed for this
   purpose. Keep it off of your skin (difficult because it dissolves
   rubber gloves). Work in the open with lots of ventilation, or better
   yet find an alternative stripper.

I know that we've all been exposed to these things in the past and
survived (me included). But really, why take the risk in the future.

Regards ... Bill