Several years ago I had a quilt that had what I thought were premanent stains on it My daughter was refinishing a piece of furniture and accidently got the wood stripping on the quilt. It ended up with small brown wood stain spots on it that resembled splotches of paint The quilt was very special to me and I was devastated. I went on line and found a recipe for a soak. I have since lost that recipe but I do remember that it contained 20 Mule Team Borax and Oxyclean ( I think thats what its called) it may have had baking soda as well, I wish I could recall. I soaked the quilt for almost a week and watched in amazement as the stain became smaller and lighter until it was totally and completely gone. I did the happy dance!
Anyway, dont give up hope. Google for the laundry recipe and soak your quilt. I'm thinking you can get that stain out with a minimal amount of effort. Geez I hope this helps...
Good Luck to you
Mikki