The type of pull switch in question (for the Ampico) looks like a
standard half-inch mount push-button, complete with stacked phenolic
insulator.  The special deal is that it is a snap-action switch (not
push-button) and it is ON when pulled out and OFF when pushed in.  The
travel is something like 3/16".  I was thinking of replacing mine with
an opto-interrupter connected to a solid state relay.  This would
require having a fleapower 5 or 10 volt source that is on all of the
time, but that is not too scary.  I think I can hide a wall wart
somewhere in the instrument.....

Another issue (question):  I have a 1929 (by the serial number) William
Knabe Ampico B grand.  It is a Louis XV or some such carved case, in
walnut veneer.  The wood is gorgeous, as expected from Knabes of that
vintage.  I have no idea what the finish is.  It has a satiny walnut
appearance.  There is no hint of alligator anywhere on the piano, so I
do not believe that it was varnished.  A couple of people have looked at
it and ventured that it was some kind of oil finish, but neither they
(nor I) are familiar with what was used at that time.

My reason for concern is that it has a few watermarks (from glasses)
that it acquired before it moved into my living room, and I'd like to
minimize them, but don't know what to do.  Any guesses?

A. B. Bonds