In this step, we remove the paper backing from the styrene parts.
One of the artifacts of the laser cutting process is the paper backing that is stuck to the styrene. I don't know why it's there, or how it effects the laser cutting process, but it's there, and it needs be removed.
The adhesive that is used to attach the paper to the plastic is not water soluble, but soaking the pieces seems to help.
Dump all the styrene pieces that were laser cut into a bowl of warm water.
Let them sit for about 10 to 15 minutes.
After the paper has softened up, user your thumb nail to get under the edge, and slowly peel off the paper backing.
Note: this is not rocket science.