Please don't use any more peroxide on your beautiful quilt; that stuff weakens fabric! Instead of trying out all kinds of removers on your quilt, I would iron some blue marker onto a scrap of the quilt fabric and try various removers on that first.
Edit: Better yet, make up several test fabrics with ironed-on marker. That way you can try soaking one in Oxyclean, using lemon juice on another, etc.