Homebrew_PCBs

> Removal of the residue is a problem. I don't think a mechanical
> contraption is a solution nor is a toothbrush.

A foam-rubber piece and hard rubbing is a very fast approach.

> I rather think that there is some kind of enzyme (septic tanks or
> used to be a laundry powder with enzymes) that would consume paper.

There is a similar ting: polishing with abrasive kitchen cleaner.
polish the top toner layer away with the paper residue.
I use paper that leaves a lot of residue and still make very professional
looking
black component legend with it. The polishing is some work but a small
tool does the trick.
Use proxxon (or other brand) minidrill and a polishing tool to do the hard
work for you.
(the felt polishing tools didn't work well for me so i mounted a small rag
over a plastic
brush tool).

> What about sticking the PCB somwhat cleaned out into the etchant in
> hopes that it will burn off the paper traces faster than copper and
> then go onto copper etching?

tried that, doesn't work. if you have paper over the holes they get dull
red but
not etched. (well, probably if you leave it long enough, but then you have
undercutting)
maybe in a spray etcher.

ST