Lye or baking soda for electrolytic cleaning - not bleach!
I am going to have to retract my recommendation in the book I wrote to use bleach as the electrolyte during the electrolytic cleaning of relics and coins. Why? Although common bleach that is used to whiten clothes will furnish the necessary ions for current flow, it is composed of a solution of sodium hypochlorite (NaClO), which decomposes partially to form sodium hydroxide (NaOH), and hypochlorous acid (HClO), it also contains significant amounts of salt (NaCl). I have used this combination for years to clean large iron relics, and it has performed well. But it’s a disaster when used to clean small items like coins, for it eats the anode and produces a slimy, discolored mess. Common lye (NaOH) or baking soda (NaHCO3) has no chlorine that can form salt or hypochlorous acid, thus they furnish the necessary ions without the damaging corrosives. Another advantage: Salt will not be present to permeate the pores of the relics and force extended periods of soaking to remove it.
I think lemon juice (citric acid) may be a fine electrolyte, for it is organic (carbon and hydrogen) and contains no sodium to form corrosive salts.
↓ Quote | PostedJune 24, 2007, 9:54 pm