Custom PCB Prototyping using a Laser Cutter

Step 4 Clean up the board

Now as you can see, the result of the lasering is beautiful, however we are not ready for etching just yet.  There is a very thin layer of paint residue left on the copper that will block the etchant solution from working properly, and will slow that process down a lot.  Here's what to do : Soak one end of a q-tip in  rubbing alcohol (ethyl or isopropyl) and spread it on the exposed copper. Try to keep it off of the black paint, because we want that to stay.  Use the other end of the q-tip to rub away, essentially polishing off the copper, making it shiny and ready for etching.  You can see in the second image, the board on the far right has been cleaned, and is shiny and ready to go.