Let me first say I don't work with either on a regular basis - I'm sure
you have LOTS of experience with Ferric Chloride.

Only on a rather steady basis since 1963 or so.



But if you've etched copper with the Muratic Acid/Hydrogen Peroxide
solution you're advocating, it will have lots of copper ions in it, and
it's the copper that makes spent Ferric Chloride a Hazardous Waste.
http://www.mgchemicals.com/techsupport/ferric_faq.html

That is correct. However, you can toss a pad of steel wool into the
muriatic acid when you are done and the copper will plate out onto the wool.
Metallic copper is not a hazmat. Steel wool is not a hazmat. Neutralized
muriatic acid is not a hazmat. Ferric chloride loaded with copper is and it
is NOT easy to precipitate out the copper from a ferric chloride solution.
That's why one accepted method of disposal is inside a concrete "septic
tank" that is then sealed.


Make no mistake, I'm not presenting Ferric Chloride as benign - it's
clearly not:
http://www.jtbaker.com/msds/englishhtml/f1080.htm

Neither is Muriatic Acid:
http://householdproducts.nlm.nih.gov...ds&id=16009010

Why do you see Muriatic Acid as less trouble? I'm genuinely curious...

Because I have to have a hazmat license to use ferric chloride in the
classroom laboratory and I can buy muriatic acid and hydrogen peroxide from
the home depot without any permits at all.

Jim