In a method of removing metals such as mercury from flue gas produced by combustion devices, water or water including a calcium-containing component or water including Cl.sup.- anion formers or water including both a calcium-containing component and Cl.sup.- anion formers is injected into the flue gas in a manner so that there are sufficient amounts of these materials in the flue gas when the flue gas is at a temperature from about 250.degree. F. to about 350.degree. F. to retain the mercury within the aqueous phase. After the water evaporates, the oxidized mercury is retained on the dry flyash particles present in the flue gas. These flyash particles bound with the oxidized mercury are removed from the flue gas by a particulate removal device, such as an electrostatic precipitator, baghouse filter or cyclone.