Dear Everyone,  Ex-USDA chemist Douglas Gregg (of "Classic Piano Doc"

on Long Island, New York) has shared with me his amazing technique

for cleaning dark and dirty old finishes using "Scrubbing Bubbles Mega

Shower Foamer", the results of which can be seen on these cheek blocks

from an Emerson Angelus that had typically dingy shellac.  The foam

was sprayed on the block to the right, then quickly scrubbed with a

fine bristle brush (to get dirt out of the fissures; a fingernail or

similarly fine brush will do), then wiped with paper towels.



The first spraying resulted in an opaque, blackish brown sludge

(soot, cigarette tar, etc.) coming out of the finish, that diminished

in intensity with subsequent foamings, until just a faint orange tint

appeared on the towels, showing that we were down to the clean shellac.

The minimal alcohol content in the mix has a slightly solvent effect

on the shellac, but not enough to remove it but slightly, and has no

effect at all on lacquer finishes (as were typically used starting in

the late 1920's) other than to clean them.



After this step, Doug says, if you want to return the finish to "like

new" without the drudgery and expense of a total case stripping and

refinishing, you can wet sand the shellac with baby oil and 320-400

grit paper to flatten it, then wipe off the excess oil, stain any bare

spots, and French polish it.  (Videos on French polishing are on

YouTube.)



Gordon Stelter

Athens, Georgia