The British Aluminium Co. recommend the following methods of treating aluminium. One method of polishing is to place in a bottle equal parts by weight of olive oil and rum, and shake until an emulsified mass results; this is used as an ordinary polishing paste. A second method is to mix together fine emery powder and tallow until a paste of suitable stiffness for use with a rag mop is formed; a final polish of great brilliancy is given by using rouge and turps on the mop. A third method is to use Vienna chalk on an ordinary chamois skin buffing-wheel, and finish with rouge; or to use a rag mop with very finely powdered Vienna chalk. For frosting the dipping bath is prepared as follows. In an iron vessel dissolve 1 part of caustic soda in 9 parts of cold water, and add about one-quarter of a part of common salt. This solution is then heated, but must not boil. The article is plunged for from fifteen to twenty seconds in the bath, so as to become nearly black on the surface and covered with air bubbles; it is then washed freely in cold water, well scrubbed with a fibre brush, again dipped and washed, then placed in a slate, aluminium, or earthenware vessel containing concentrated nitric acid until the metal becomes quite white.

Again rinse in cold water, and finally dry in warm dry sawdust. Metal thus treated takes a very beautiful matt, which keeps for an indefinite period in the air and has a silky appearance, and the frosted aluminium does not blacken the hands.