It has been discovered that metals can be removed or transferred from a hydrocarbon phase to a water phase in an emulsion breaking process by using a composition that contains a demulsifier (for instance, an oxyalkylated alkyl resin and/or a crosslinked polypropylene glycol), a surfactant, a diketone and a solvent (for instance an aromatic solvent). The method may also include introducing a hydroxyl carboxylic acid and/or at least one mineral acid to reduce the pH of the desalter wash water. The method permits transfer of metals into the aqueous phase with little or no hydrocarbon phase undercarry into the aqueous phase. The composition is particularly useful in treating crude oil emulsions, and in removing iron therefrom.