Which do you prefer? I have the option to do both but milling seems to take awfully long and produces a lot of noise and glass fiber dust. It has the benefit of not needing etch resist which is also messy.
Chemical etching with iron chloride is also quite messy. First applying etch resist, removing part of it, etching etc. It is much simpler though and you don’t need a CNC machine for this.
Yes I’ve tried that as well. It’s way better than messing with toner transfer or those etch resist foils/spray.
It also works well for solder mask. If you apply one white layer and a green layer on top of that you can make decent part labels by lasering away only the green top layer.