I have had problems with stains on quilts that respond to simple old aspirin. I buy a bottle of cheap stuff and then put a couple in a cereal bowl, add some water and use a sponge pain brush and dab it where the stain is. Let it dry and repeat. Took some old spaghetti stains out of a quilt that had been in the cupboard for a few years after it was laundered. It took about 9 "coats" of the aspirin mix. Just let it air dry see if the stain continues to get lighter and keep trying.