The pickle maybe biodegradable, but if the residue is the blue/green
of copper oxide, the copper oxide is somewhat toxic to most
organisms. I've understood that a quart or so of spent pickle can
"kill" a private household type septic system. So unless you first
precipitate out the copper oxide somehow, the "biodegradability" is
to me suspect?
Yes, the citric acid I use, in it's un-used state, is a food grade
acid, a prominent ingredient to many soft drinks, candies and some
baby foods. Once "contaminated" with copper oxide, bad stuff,
dispose carefully, but it is effective and not as environmentally
reactive as sulfuric acid and it's derivatives.
Yes, by the way I was taught to mix it, at room temp it doesn't
dissolve fully till heated then it should stay in solution, so it's
not quite a super saturated solution, just in the neighborhood.
QUESTIONS: Is there a litmus or hydrometer test "standard" for
Citric? or for Sulfuric for that matter? And would some standard
bench mark indicate when the pickle is fully used, other than color
Hoping my comments and questions help others as well,