If your fabric is something that frays, there's also cutting it for the shape you want, running a straight stitch along the edge about 1/4 inch in, then washing it. That'd give it a little bit of a frayed look.
We usually just used the cut/stitch/washer method, a rasp. or sandpaper when we weathered things for plays. Nail files weren't that great for covering large areas, but worked well for small detailing.