Even when you do everything right, this is what can happen. This is one of my old garage sale finds and one of the first quilts I get out when we have a chill in the air.
To my surprise, this is what I unfolded and found. I think this quilt was $20 at a garage sale, the outside border was a mess and I cut that all off and put new binding on it and it's been used and washed for 10 years plus. I store it in acid free tissue and then in a white 100% cotton pillowcase, like them all. So, I figured I'd see if I could fix it.
I made a paste of liquid laundry detergent and non-chlorine all fabric bleach. I know some of you just gasped, but I know me and if it was there, it would drive me NUTS. Laying it out on the kitchen counter, I wet the section, and working in my mixture, and let it set for some time. Rinsed it well and washed it on gentle and the pictures are the quilt drying on the clothes line.
The side with the stain was in the full sun for the day and as you can see, it looks wonderful. bethanndoing.com