That is beautiful Celeste. What shape is used to make up those flowers? At first I thought they were Hexagons you know like a Grandmother's garden... But no, and then I thought "triangles" but that's not right either, are they 60 degree diamonds?
VINEGAR! Soak the entire thing in Vinegar, straight. You can get a gallon pretty cheap at the gocery store. Then soak it. Every half hour to an hour move it around in the bucket.
I had a crazy age stain on some very special fabric and I was amazed by how well it worked. Just last night I was looking at it in the quilt I made with it and was astonished at how it looked like "new!" The vinegar will get "groady" like oily tea, but pay it no mind, as it wont remanifest on the quilt, you'll just have to wash your hands with dishsoap (or Renee will) after every swishing.