The HCl, incidentally, is the chemical formula for hydrogen chloride, which in aqueous solution becomes hydrochloric acid, one of the strongest acids (pH < 7) there is (in fact, it's a major component of stomach acid). It's also fairly commonly available in chemistry classes, along with its basic (pH > 7) counterpart, sodium hydroxide (NaOH). When combined, they form salt water, NaCl + H2O (which, as you might guess, is where they get these two chemicals from, separating out the Na and Cl using electrolysis, then recombining in pure water to form acids and bases).
Err, anyway, the chemistry lesson may provide some insight into the choice of nickname, or it may not.