I own 2 vintage u87s. They both came with black vinyl covered cases that have a silver locking clasp. In the lower part of the case, there's a holder for the microphone to sit in, and in the lid, there's foam covered with red fabric that cushions the microphone from above.
My problem is that all of the foam in one my cases seems to have disintegrated. It's all dried out and crumbles at the slightest touch, making a big mess in the case and on the microphone.
My question is - why has this happened? Did the foam break down because it's old, or is it due to high humidity? Do I need to worry about damage to the microphone if it was stored in the case? This has only happened in one my cases, is this likely to happen in the other?