Homebrew PCBs

Brian Lalor <blalor@...> writes:
> > Don't dispose of them!  The acid/peroxide etchant becomes CuCl etchant
> > with use, which can be air regenerated and used over and over again.
> 
> What if you really really need to? :-)  Baking soda?

IIRC you add a base (sodium hydroxide (drain cleaner) if you have it,
else baking soda) until the copper precipitates.  That tells you the
pH has just passed neutral.  Let the water evaporate, leaving a copper
salt "brick" at the bottom.  Bring that to a hazmat place.