I've used my step-dad's jeans and cowboy shirts to make a Denim Stars quilt. Some of the shirts were a little thin, but they are protected with the denim wrapped around them. Can't find a picture of the finished quilt, but you can see how it's made. You sew octagons of denim together in 9-patches. Then put squares of batting and the shirt squares under the pointed flaps. Then fold the flaps down and finish the raw edges with zig-zag stitch. The back of the quilt is denim squares.
You can do the same with squares or brick shapes -- Brick Work or Windows Denim Quilt pattern