I use the pants shortening leftovers for testing machines that I need to get tensions right or even see if they sew! Sounds silly but why waste "good" fabric doing that when those leftovers are fabulous. I use my old, old thin pillowcases for testing decorative stitches on the vintage machines. They are being useful and I am not wasting good fabric on that project either. Perhaps these only apply in my situation but it's how I use up some stuff that might otherwise go into the trash. I admit that I'm no longer obsessive about ripping out the stitches and reusing 5 or 6 times before trashing the fabric but I might use it twice over and every single iota of space is filled up.