Following are several ideas:
Resolve stain remover for laundry, Shout, Mr. Clean Magic Eraser, Grandma's Secret Spot Remover, make a paste of the Oxygen/Oxyclean and work with a washcloth in small areas, rinsing well, white vinegar on a rag blotting the area, soda seltzer water.
Good luck, keep us updating on the outcome.
Pam M