Sandpaper with a light touch might work to help along the sides - that could make for subtle wear. I think that the sides would receives less wear than the hem.
For the bottom edge, some advice I've seen on the forums, and things that occur to me, in any order or combination could work:
-drag it along behind on pavement, gravel, and grass.
-Tie it against a tree or fencepost and whack the bottom couple inches with a stick or metal pipe or both
-drive over it
-light it on fire a little (natural fibers only) and put it out.
- lay it on concrete and rub bricks or cinder blocks over it randomly
- rub it through gloved hands along the whole length of the hem.
- twist it up and shake it out repeatedly
- wash and dry it several times
Hope this helps and good luck vod.