The one thing we all hate about the laser cutter: burnt edges. You mitigate this by masking the material with wide painter's tape before cutting, but even with that you still get soot coated edges. Here's an instructable on how to quickly and easily get rid of laser burn.
All you need is a little pumice liquid soap and a brush. A toothbrush would probably work best, but this fabric brush did the job for me. You can easily get the burn marks off the face of the wood with sandpaper, but it's practically impossible to get into tiny crevices with sandpaper.
The pumice granules act like sandpaper and the brush bristles allow you to reach tight spaces (just like the toothbrush companies promise in their ads) and scrape off the ashes.