In an inconspicuous spot try a little "IRON-OUT". Dilute it (1/4 tsp) in a small cup or bowl of warm water. use a cotton ball or Q-Tip and dab it. Let it sit for a minute or so and keep an eye on it. Then flip that small area over and run water over it to rinse. By doing it this way (flipping it over) when you rinse it won't run into the other side of the quilt. My grandmother used to use Cascade dishwasher soap. She would use the same measures.