What is your technique? I went to the Shipshewana Quilt Festival in June and an expert advised that we think carefully before we wash our antique heirloom quilts but you have obviously succeeded. She said we can safely vacuum old quilts if we lay clean windowscreen down over the quilt and vacuum through the screen. I would appreciate your tips because I have some old quilts that are stained like yours was.
Here's a link to a blog where I describe what I did: http://willywonkyquilts.blogspot.com/2013/09/washing.html