A method for reducing tin in lead bullion has the steps of adding an Arrhenius base to a kettle containing lead bullion and tin, adding a byproduct of conventional detinning to the kettle, agitating contents of the kettle, and removing a layer of slag from the kettle. The disclosed method removes tin via chemical oxidation, adds lead via chemical reduction of an oxide from the byproduct of conventional detinning, and preserves most of the antimony content of the lead bullion.