I periodically go thru my stash and pull out fabrics that maybe I'm not quite so in love with anymore and I cut them into 2" strips, 3 1/2", 4", 5" sometimes 6". Whatever odd size pieces are left I put in my "scrap" boxes.
Love scraps too! Miss working at the fabric store I used to and only two LQS here have scrap bins. One sells by the piece, the other sells by the sandwich ziploc size.