I would not feel comfortable in using it as it is not 100% cotton. I have to be careful too with what thread I use when making microwave things because much of my thread is a cotton/polly blend. Fabric, batting and thread should all be 100% cotton to be on the safe side. I had heard that Warm Company is no longer making Warm Tater which came in a package but I bought some Warm Company 100% cotton by the yard recently at a quilt shop. It is 24" wide.