Really need to know what the origin is first. How big it is and what kind of material is it on. Hopefully, you haven't tossed into the dryer but often we don't see them til we pull them out after drying. In a dishpan Try a mixture of Dawn and vinegar. let it sit for 20-30 minutes. or you can let it set in a mix of Dawn and ammonia. Agitate it a little. Then rinse and see if that helps.