I think that I've heard of someoneputting cast balls in a bucket of sand and letting it roll around in the back of their truck, to both wear down the sprues and seams,and tocreate very small dimples in the surface of theballs. The dimples are said to result in giving the patch a better grip on the ball and maybe it helps toimpart a better spin on the ball too, at leastin theory.
Why do they put dimples on golf balls anyway?