Some people use vinegar or soy sauce instead of pure acetic acid, but the impurities complicate resist laydown in photogravure. A good working solution is eight parts water to one part each of acetic acid and salt by volume. Skin and eye contact with NaOH are dangerous, but it is not volatile. Rubber gloves are essential for mixing and using sodium hydroxide. Small quantities of sodium hydroxide can safely be poured down the drain, as it is the active ingredient in drain cleaner.
Ammonia is highly corrosive to the eyes.
These substitutes require more effort to remove etching ink, but are non-volatile and safe to use. Organic Solvents . Organic solvents, used in cleaning up inks and etching grounds, are among the most common and insidious poisons found in the printmaking workshop. The effects of breathing the fumes of organic solvents such as benzene, toluene, xylene, turpentine, mineral spirits, methyl alcohol, gasoline, and others may be spread over years. Each bit of harmless-seeming exposure adds up to more likely illness.