Yes, I pre-wash everything; even the small 2"X3"'s from a pre-cut mini kit. I have white fabrics for this pre-wash purpose. I layer two to five similar sized new fabrics on top of the white fabric. I 'fold/wrap' the white fabric over the raw edges of the new fabric. Then I machine baste all around the perimeter being sure to secure the raw edges within the folded area of the white fabric. Wash in hot, dry hot. Voila! Then I rip out the basting stitches. Because the white fabric has protected the raw edges there is no fraying. I know it is anal but it fits my personality! Please just hope that I am never your boss!!!! HaHaHaHa