Actually its not that hard, it is like silkscreening a board to etch it but in reverse with conductive paint instead of etching protector. I've done this before with the good doctor for the Big Apple Group for one of his Apple II ROM Boards he created. Not that I expected to make buku amounts of money with it, but it was fun doing it.

But as we know, all Mac Boards are multi-layered and this would only restore the top layer. Who knows what condition the other layers are in.