SOL-20 keyboard question

The SOL-20 has powered up, but the keyboard is sorta FUBARed. The LEDs work, but none of the keys do. I pulled the keyboard, and shorted a couple row & column drivers, and the keystrobe strobed. I ended up removing the PCB from the key assembly, and determined that pads inside the keys are shot to hell. They look like they should be mylar coated or silvered Kapton discs with a foam backing. The foam is mostly decayed, and there's virtually no silvering left on any of the discs. They few that do have only the slightest fragments. I assume this is supposed to be conductive, because pressing a disc against the PCB pads doesn't trigger a key, while touching the PCB with my finger does. Can these be rebuilt, or are replacement switches available? --jc