I had some fabric square from the 1800's that had been passed down. They were cream colored and had yellow stains from age. I soaked mine in a weak solution of lemon juice and warm water. (I did test a small piece first to make sure it wouldn't damange it). After the soak, I rinsed them well in cold water and hung them on the clothesline outside in full sun. The stains came right out and the fabric survived to be made into a quilt that is still being used.