Sergio,
I clearly stated "hardware store muriatic acid and drugstore hydrogen=20
peroxide"  Should I have added "full strength"?
There would be only the smallest traces of copper left after=20
precipitating with baking soda.  Copper is not like mercury or lead in=20
that neither of them have a minimum daily requirement - copper does. We=20
use copper pipes for our water, copper coated scrub thingeys, etc, etc.=20
we used to use CuSO4 to kill roots in the sewer lines but that WAS tough=20
on the sewage treatment plants.
If you wish to remove any final traces of copper, first test some of the=20
suspect clear solution with a dollop of household ammonia, any=20
significant copper will turn the resulting solution blue - if the test=20
fails, electrolyze out the remaining copper or even just throw in some=20
steel wool to scavenge the copper out.
What I should have mentioned is that you should not throw away the=20
solution anyway cause "they" say it regenerates with exposure to air and=20
can be used over and over. I don't do that much etching so I toss mine.

"
Not wishing to be a kill-joy here BUT...

"two parts hydrogen peroxide for every one part hydrochloric acid"

Doesn't really tell me a lot. What are the concentrations of these liquids
before you mix them?

Also, mixing "baking soda" with copper chloride (the result of etching
copper metal with HCL and H2O2) does ***NOT*** result in pure water +
solids, there will be some copper ions left in solution. You really
shouldn't just flush this down the drain as a mater of course.

Regards
Sergio Masci
"
--=20

Looking forward,
Al Shinn

--=20
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