The fluxing material can be added to the molten metal immediately before, during, or immediately after the charging of the metal scrap. It is conventional to use a compressed air "lance" to thoroughly agitate the flux with the molten metal until the reaction is complete. At that point the flux containing the trapped metal impurities remains in a semifluid condition and floats on the surface of the molten aluminum metal. This dross can then be removed by skimming.