Now that we've removed the paper backing from the styrene parts, we need to do a bit more clean up. If you take a close look at the various laser cut parts, you'll see that there is sometimes some melted styrene around the edges where the laser got a little too hot, or stayed in one place for a little too long. I'm not talking about the texture inside the cuts, I'm talking about little styrene blisters that have melted onto the flat surfaces.
Here we clean those up, and get rid of some burn marks.
Take some high grit sandpaper, say about 600, and run it over the edges of each piece. You don't want to reshape the styrene pieces, or flatten them out. You just want to "deburr" the edges, and get rid of the zits that may have developed during the cutting.
Here's an example of a cleaned up piece. It might be hard to see the differences from these pictures, so use your best judgment.