I would let it soak overnite. I use "Linen Wash" by LeBlanc located in Seminole Fl. I had bought this at my LQS many years ago. I also saw it being sold in a chain linen store but then they went out of business. I had a client who actually iron her quilt without first removing the blue b gone. I soaked the quilt overnight and I was SHOCKED to see that all the blue b gone was gone. Customer was absolute delighted.