Lance, that's a superb question.
A brilliant chemist / inventor has developed a procedure in which a
photographic emulsion can be non destructively removed from its original old
paper and transferred to new material. I've seen samples of this terrific
achievement at the Photography Department of the Musuem Of Art here in NYC.
I can't recall the name of the vendor who developed the method, but
certainly the curators there know.
Even for disks that have broken into pieces, this might have important
potential for retrieving sound from such broken & damaged media.