I don't have an answer either. I bought some fabric at a yard sale recently and some of it was so brittle that it almost fell apart in my hands. On the other hand, I have a quilt that my MIL mother made I don't know how many years ago and it seems to be ok...My MIL died several years ago in her 80's, so I don't know when her mom made that quilt...... It is a Sunbonnet Sue and the dresses are all from fabric of her childhood friends, along with their names ! it is awesome.
On another note, if you ever want to get rid of that baby that is your avatar, keep me in mind!