Dross, which is the oxide-rich surface that forms on melts due to exposure to air, is a term that is usually applied to nonferrous melts, specifically the lighter alloys such as aluminum or magnesium. This article describes dross formation, economic implications of dross, in-plant enhancement or recovery of dross, and ways to reduce dross formation. It discusses the influence of melter type on dross generation and the influence of charge materials and operating practices on melt loss. Fluxing is a word applied in a broad sense to a number of melt treating methods. The article discusses in-furnace treatment with chemical fluxes.