This page says that Edison started out using a hybrid of celluloid and condensite:

http://turtleservices.com/eddtechnology.htm

Then, in 1916, he began using only condensite as the recording surface. But, if he recommended alcohol as a cleaner, it could be that the additives in rubbing alcohol are causing the problem. 

Best,
Gary

____________________________

Gary Galo
Audio Engineer Emeritus
The Crane School of Music
SUNY at Potsdam, NY 13676

"Great art presupposes the alert mind of the educated listener."
Arnold Schoenberg

"A true artist doesn't want to be admired, he wants to be believed."
Igor Markevitch


-----Original Message-----
From: Association for Recorded Sound Discussion List [mailto:[log in to unmask]] On Behalf Of David Breneman
Sent: Thursday, May 24, 2018 3:07 PM
To: [log in to unmask]
Subject: [ARSCLIST] AW: [ARSCLIST] Cleaning Diamond Discs with Grain Alcohol

Von: "Gary A. Galo" <[log in to unmask]>


> I believe alcohol is a solvent to the celluloid surface on a
> Diamond Disc. It's also a solvent to shellac, so it shouldn't be
> used on the vast majority of "78-rpm" records. 

The surface of a Diamond Disc is a proprietary polymer called
Condensite.  I don't know if it's related in formulation to celluloid,
but the Edison company recommended cleaning Diamond Discs
with alcohol.  I'm trying to find out if one specific category of
alcohol, like rubbing alcohol, will work safely while others, like
grain alcohol, will not.  I've always avoided rubbing alcohol for
most cleaning chores because it contains a lot of extra ingredients
besides the alcohol itself.