Get you some Oxiclean for laundry and make the solution stronger than what they call for. I would put the quilt in my washing machine and about six big scoops of OxiClean or at least 12 if the scoop is small and wash in on gentle cycle. Once the soap and oxiclean have dissolved after washing a few minutes, stop the washer and let it soak for several hours and then finish washing the quilt. I have found a strong solution of Oxiclean has helped me out so many times it is unbelievable. The stuff isn't cheap, but it sure does the trick if you make it much stronger than what they call for. So far it hasn't discolored anything I have used it one and believe me I use it on just about anything and everything. Good luck.
themachinelady