Scratch brushing. Use a fine brass bristle brush and pumice powder a
little detergent, washing up liquid, helps. Obviously brush all in
the same direction. Some kitchen cleaning agents have pumice in it
to give abrasive ffect, experiment with this if its available. We
used to have a rotary scratch brush set up on a low speed polishing
motor turning with water mixed with detergent dripping onto it as it
rotated. Used to apply the pumice powder in paste form to the job
and then scratch with the rotating brush. You can get a satin
polishing media which you use on a bristle mop but it's a bit
aggressive so go carefully.
Hope this helps. Hamish
