NOVELTY - Producing (P1) deicing and/or anti-icing agent (A1) comprising glycerol and salt involves processing by-product from alkali catalyzed triglyceride transesterification process for the production of monoesters, by-product comprising glycerol, water and salt and optionally further comprising fatty acids and/or other organic compounds other than glycerol; employing acid to neutralize the by-product to reduce pH and convert alkali catalyst to salt and to neutralize and separate free fatty acid; and utilizing process to recover part of glycerol as salt-free stream having glycerol and water.    USE - For producing deicing and/or anti-icing agent comprising glycerol and salt, which is useful for preventing ice formation in, or removing ice from, surfaces and liquids, where the surface is selected from pedestrian walkways or vehicular roadways, highways, bridges, parking facilities, aircraft surfaces comprising wings, fuselage or tail surfaces, airport runways or taxiways, decks or portions of a superstructure of a ship, exposed industrial equipment, and surfaces of particles of coal, ores, sand and gravel, and the liquid is selected from fire extinguisher fluid, hydraulic fluids, lavatory fluids, heat transfer agent, and well drilling fluid (claimed); and for the application to engine fuel i.e. biodiesel.    ADVANTAGE - The obtained deicing and/or anti-icing agent provides excellent deicing and/or anti-icing compositions that are more environmentally benign and are prepared from relatively inexpensive raw materials while still possessing desirable freezing point depression properties; and is free from or significantly reduce the use of inorganic salts.    DETAILED DESCRIPTION - Producing (P1) a deicing and/or anti-icing agent (A1) comprising glycerol and salt(s), involves processing a by-product from an alkali catalyzed triglyceride transesterification process for the production of monoesters, the by-product comprising glycerol, water and salt(s) and optionally further comprising fatty acids and/or other organic compounds other than glycerol; employing an acid to neutralize the by-product to reduce pH and at least partially convert the alkali catalyst to salt(s) and to neutralize and separate at least part of the free fatty acid; and utilizing a process to recover part of the glycerol as a salt-free stream comprising glycerol and water, by removing an impure stream comprising the unrecovered glycerol, together with all of the salt(s), and optionally the organic compounds other than glycerol, where the deicing and/or anti-icing agent comprises the impure stream. INDEPENDENT CLAIMS are included for the following:    (1) a deicing and/or anti-icing composition (C1) comprising the deicing and/or anti-icing agent (A1);    (2) a deicing and/or anti-icing formulation (F1) comprising the salt-free stream comprising glycerol and water of agent (A1);    (3) preventing (P2) ice formation in, or removing ice from, surfaces and liquids, involving employing the deicing and/or anti-icing composition (C1) and formulation (F1).