The fluxing material is usually a blend of sodium and potassium chlorides to which approximately five percent of cryolite (sodium aluminum fluoride) is added to promote melting of the scrap aluminum charged to the furnace for smelting. The ratio of potassium chloride to sodium chloride may also vary as required. Conventionally the amount of fluxing material used can vary widely depending upon the composition of the scrap aluminum to be processed. Typically, the flux amounts to about ten percent of the metal scrap charged to the furnace or metal bath. 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.