When electrical etching mild steel with a salt solution, add some citric acid to the salt solution. It keeps the nasty gunk out and speeds up the etch.
Might the citric acid also help to reduce the crud when electro
etching copper and brass with salt water?
I was told that this “crud” is “sodium hydroxide (lye) and copper
chloride”. After the etch bath sits overnight, this crud settles to
the bottom of the tank. I syphon off the clear solution to re-use
(with added salt) and pour the crud into a bottle to take to the
hazardous waste site. I am very careful to wear proper gloves to
protect my skin at all times. Also safety goggles. just in case.
Carol Holaday