Beautiful quilt and a great job by all. I would contact a museum or a gal that does apprasials on old quilts before you try to wash or clean it. An appraier can tell you the age of the fabric and can tell you howe to care for it. This is on advice from Linda Honsberger, she is a certified appraiser. She is out the Racine, Wisconsin area.
Hope this is of some help to you. Pat