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Hi Mike, For over 25 yrs. we have demonstrated that it is indeed possible to safely & thoroughly clean Diamond Discs with a water-based blend of ionic & non-ionic surfactants when used as directed. Users include individuals & institutions nationally & internationally, some of whom are members of this list. Household soaps & detergents are not thorough cleaners of disc phonograph recordings even with a simple rinse. Trace residues can act as feedstock for biological growth & interfere with accurate playback. Regards, Duane Goldman On Apr 24, 2012, at 5:08 PM, Michael Biel wrote: > From: Roger Kulp <[log in to unmask]> >> Could someone tell me why the surfaces of so many Diamond Discs seem >> to flake and peel off,leaving the core exposed? Roger > > This was a problem in the earlier years because the surfaces were a > celluloid sheet laid on a wood-flour core. The wood-flour core would > absorb water which is why Edison discs must NEVER be washed. The rims > start to spread and separate, and the celluloid will curl. The three > dimples in the label area were supposed to help keep the celluloid layer > secure, and they continued to have the dimples in later years when the > top surface was changed to a liquid called Condensite which hardened > with the pressure of the press with pressing times between 20 and 40 > minutes. The core material became changed to clay which did not absorb > water. This started during the war years when quality materials were > scarce, and the surfaces were not quiet for several years. It was > finally when they started using the paper labels in the early 20s that > the disc surfaces became quieter. > > Mike Biel [log in to unmask] H D Goldman Lagniappe Chemicals Ltd. PO Box 37066 St. Louis, MO 63141 USA v/f 314 205 1388 [log in to unmask]