The zipper on my eleven-year-old dulcimer case finally quit. No matter what I do to lubricate the zipper teeth or tighten the pulls, the zipper stays stubbornly separated. Tired of closing the case with a couple dozen quilt-basting safety pins, I found two long zippers in my sewing supplies, both from bedding packages, and stitched them to the existing zipper. So far, so good. Certainly better than all those pins!