Thank you for all your comments. From the description on the web site, 
the sleeves I have encountered look a lot like these:

So I assume these are at least similar to the shield-packs. None of them 
are sealed, and, again, the records appear to be in mostly good shape.

However, I do not see archival boxes that are big enough to vertically 
hold the discs in these sleeves (with their broader seams), which I 
assume is the way to go. How are institutions that use the shield-packs 
storing their discs?

Thanks again


Robert Hodge wrote:
> We have lacquers which have been in stored successfully in shield pack
> sleeves for 15 or more years. 
> None has ever been sealed.  
> The discs which have been recently inspected at random are still in the
> same condition as they were received. 
> Our choice of the shield pack sleeves was based on the LOC use of them.
> We didn't seal them for the same reason.
> Bob Hodge
> Robert Hodge,
> Senior Engineer
> Belfer Audio Archive
> Syracuse University
> 222 Waverly Ave .
> Syracuse N.Y. 13244-2010
> 315-443- 7971
> FAX-315-443-4866
>>>> [log in to unmask] 2/14/2007 10:58 AM >>>
> 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