An additive and method of use for treating flue gas of a coke-fired cupola following removal of the blast air during shutdown to adjust the charge and reduce acid buildup in the condensate and corrosion in downstream equipment by injecting into the flue gas a finely divided spray comprising an additive containing a volatile amine mixed with an antistatic agent that creates a positive static charge in the additive, and elevates the pH of the condensate by reducing the formation of sulfuric acid from entrained sulfur-containing compounds.