Making gelatine discs supple again?

We plan on digitizing some gelatin discs from the 1930s ("system Domofon", produced by a long-since-perished Swiss enterprise), but they seem to have become warped and rigid, perhaps due to too dry storing conditions, barring any possibility of playing them back with a turntable and a needle. Do you know of any reports or publications that describe possibilities of re-moisturizing the discs in the hope of getting them to become less warped, perhaps even supple? I was thinking along the lines of putting them in a humid environment (e.g. an aquarium with an open cup of water) for a certain amount of time, before playing them back conventionally? There are optical ways of recovering the sound, but the costs are so tremendous (ca. USD 400 per record side[!]) that it is beyond question for our small institution. Thank you for any kind of assistance, Dieter Studer-Joho, Phonogrammarchiv der Universität Zürich, Zurich, Switzerland, URL: .

Maybe as a complement to the above request, our engineers here at the Swiss National Sound Archives have quite some experience in "flattening" records, of all kinds... unfortunately with lots of failures, which is not what we wanted for the Phonogrammarchiv, thus the suggestion to do it optically. We would be very interested too in a reliable, non-destructive solution for treating heavily warped gelatin discs.