What I am doing w/leftover scraps of batting
I recently had saved some of the narrow, "useless" long pieces of batting that had been trimmed from a project when squaring up. And I recently was making a small pillow and did not have a filler.
I tossed and scattered the scraps onto my cutting mat, laid a ruler atop, and cut those scraps into bits which I then used to fill the pillow. Worked great!