And for all you thinking that they are flexible still by accident, not so much!

Take your antique patches and wash them in a sinkful of warm soapy water with a capful of Chlorox. Rinse well and work a little fabric softener into them before rinsing well and drying. They will soak up enough water to become very workable and you will have stopped any impending bug attacks at the same time... It will also let/force you to look at what you have...

I once found a Hoffman #1 grizzly saddle in my collection completely eaten up by moths, right in the middle of my stuff, in a zip-lock. Just a mass of feathers perfectly arranged with nothing but friction holding them together.... A few critters in various life stages there as witness to the damage they had done.