Cleaning off my camera card, I found this picture. When I first received the moria mold from keebler studios I whipped something together and sent a picture back to them thanking them for the mold.
John at Keebler recommended a step which I now use to add wear and tear or aging to my columns or other projects made with plaster.
After making the brick and after it is dry, throw it into a paper bag with other bricks and shake it for a while. This smooths the sharp edges and makes them look worn.
You do have to wipe the pieces down afterwards before painting, as they will be covered in dust.
Unshaken column on the left, worn one on the right. Not the best picture but I think you can see the difference at the top.