We still use the Shield Pack sleeves for lacquer discs here at LC. I believe that the issue of inhibited air exchange arose from a very early practice of sealing the discs in the sleeves. Obviously that was a bad idea. Otherwise, we have not noted any problems with air exchange or accelerated degradation of lacquers. The only problem we have had with the sleeves - and this was with a later "batch" we had manufactured - was that the sleeves arrived badly warped. These we only use for rigid discs - glass or metal-based lacquers - and not for more pliable vinyl or even shellac. Gene DeAnna Head, Recorded Sound Section MBRS Division Library of Congress (202) 707-3108 >>> <[log in to unmask]> 02/14/07 9:44 AM >>> >2. Is anyone familiar with foil-lined sleeves? I have not seen any imprinting or other problems with the discs, but is there concern of outgassing or any other problems? Marcos, These may be a type of sleeve known as the "shield pack". As far as I kno w they have been discontinued not because the sleeves off-gassed but, because they inhibited air exchange (i.e. created a micro-environment)and seemed to in fact accelerate the degradation of lacquered discs, which of course do off-gas. I seem to recall that they were developed at least in part by the Library of Congress and, if that's so, someone from LC could probably give you a more complete history. Best, Danny Daniel Sbardella The New York Public Library for the Performing Arts 40 Lincoln Center Plaza New York, NY 10023 212.870.1609