Thanks!
Buzz, Midway USA sells a tool for jeweling, it is essentially a brass tube with an abrasive rod inside it. It has an adjustment plug in the end, to push the rod out as you use it up. They also sell replacement rods. They feel like long pencil erasers with fine abrasive in it.
You can also smear valve grinding compound on the blade, and use a hard plastic rod. Works fine, but is a bit messy.
Dan