There are tons of people who would love vintage 30's fabric. (I'm one of them.) In fact, I concur with ptquilts about emailing a quilt guild.
Historical societies usually have many more donations than they can display (and the only people interested in old quilt fabric is quilters).
Don't give it to a thrift shop. I'm basing this on the fact that I never see any quilt fabric in a thrift shop. I believe it gets bundled in with the unsellable clothes, at least here in DFW. One person who posted here previously was in the Seattle(?) area and found lots of quilting fabric in thrift stores. Obviously, all areas are not the same.
bkay