The oil should be macerated two or three days at least upon about an eighth of its weight of litharge, in a warm place, occasionally shaking the mixture, after which it should be left to settle and clear; or it may be prepared, without heat, by levigating the litharge in the oil. Acetate of lead may be substituted for litharge, being soluble with less heat, and its acid, being volatile, escapes during solution and bleaches the oil, to which coarse smalt may be added to clear it by subsidence, increase its drying and neutralize its brown color. This affords pale drying oil for light and bright colors.