I liked that the solution you use for the etching is not going to degrade no matter how many plates you make. Also there are no toxic gases released during the etching process. The complete guide I studied and used for my tests can be found here.

I am currently still making test plates, but the results look promising. To keep the process as non-toxic as possible I used Amsterdam Acrylic markers, Lascaux Hard Ground and lithography pencil for my first test plates.


Results:
First step test-plate was made using only acrylic markers. I drew with the markers and used them also as the stop-out varnish. They were in 3 different sizes and had different paint solutions - transparent, semi-transparent and fully covering. Clearly the markers started to erode but the conclusion is that the best protection was achieved by the semi-transparent one.
For the second plate I made a drawing with the lithography pencil (soft). After the initial 15 minutes of etching I used Lascaux Hard Ground as a stop-out.
For the third plate I drew with the same markers as before but used Lascaux Hard Ground as the stop-out.

After the plates had been etched I used the non-toxic (but potentially irritating- wear gloves) soda-ash solution and a toothbrush to strip the paint from the plates.

I also tried the Pebeo acrylic paint remover witch worked faster but I am not entirely sure about the safety as the ingredients are not listed on the bottle. It smells, is regarded irritating but can be washed of with tap water. I have yet to test the power of the Orange oil cleaner witch should work as well.