Vacuum & Clean
Once the milling is complete, you'll need to use a vacuum to clean up all of the dust and excess material. It may be difficult to get behind the spoil board, so I tend to use the move commands, Re-Home, Origin, and Loading. Click these will move the spoil board.
Scotch Brite Pad
The edges of the traces might have burrs. I like to use a scotch brite pad and lightly sand the top surface of the PCB. A few passes for a minute will smooth out the edges and make the cooper look shine and clean. This will introduce new dust, so you may need to use the vacuum again.
Next up we can work on removing the PCBs from the spoil board. The adhesive in the double-sided tape is fairly tough, so I do not recommend prying the PCB off. That could bend the PCB or damage the board. So I use a squeeze bottle with alcohol and pour it onto the edges of the PCB. This will soften the adhesive and make removal easier.
Let the alcohol soak underneath the PCB for a moment. Then, use a thin spatula or palette knife to get in between the PCB and spoil board. Be very careful not to scratch either surface. I try to get in between the strips of tape. Once under the PCB, slowly begin to lift to remove the PCB. Apply more alcohol is needed.
With the PCB blank removed from the spoil board, we'll need to remove the PCBs from the FR-1 blank. I suggest doing this over a waste bit so it can catch dust and debris. If the board outline wasn't cut all the way through the material, you'll need to use a knife, blade or similar to cut it out of the blank. Dust tends to accumulate in the board outline. Use a scotch brite pad to smooth out the edges. Use a pair of tweezers or needle to poke out the holes.
Thoroughly inspect the traces and holes. Make sure all of the burrs and dust has been removed from the traces and holes. Bare copper will eventually oxidize and begin to rust. You can protect the surface with UV curable solder mask or similar. We have a learn guide on that topic, as it is not covered in this project.