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.