Originally Posted by sassy granny

Try soaking the quilt in Calgon water. I tried it years ago to soak rusty hard water stains out of baby diapers and it worked. I don't remember how much I used but it was probably close to a whole box in a big tub of water. I let them soak overnight and then washed them regular wash and hung them out in the sun and they were white as snow. I always used it to whiten my clothes because I had hard iron water, before we got hooked up to a public water system.