I have starched flannel for quilting, but I starch the "wrong" side, so the starch is on the inside of the "sandwich". That gives the flannel more body, less puckering, and it lies more smoothly more easily. Plus you don't have to deal with the starch "smoothing down" the nap of the flannel on the outside. I always wash my quilts when finished, so the starch comes out then anyway. No one taught me this. It was just trial and error.