AI made some figures from Rice Krispies treats, then dipped them in chocolate to harden. The problem was I could not get the chocolate smooth and knew it would look horrid under the fondant. I mentioned to my husband that I wished I had some kind of food safe sandpaper. He suggested I use our broken fine-mesh tea strainer. It worked great! The figures are really smooth now.
This is the kind of tea strainer I used. Ours is broken, so I only used half. It is dishwasher safe. http://www.amazon.com/b?ie=UTF8&node=3737181
The other benefit is that the chocolate dust stayed in the strainer, then I just knocked it into a bowl. If you need chocolate dust, this is a good way to make it.