There are different methods for a matt-finish on precious metals.
In our gold-smith courses (tp-gold.com)
we mainly use these possibilities:
< The surface gets worked with sandpaper.
a) with a 240 granulation in one direction or crosswise or circular.
b) with a 40 granulated woodsandpaper circular.
You have to work on the whole surface repeatedly. Only if you do that, the surface gets evenly.
< Alternativly you can brush the surface with scrubbing powder.
c) The surface gets brushed with old toothbrushs, pumice-meal and water.
You can also use a brassbrush, a fine steelbrush or household sponges. You can get very nice effects by alternating matt and polished surfaces.
You find more information and filmclips about matt-finish and polishing in Tutorial No.2 - Just click "HERE"
We mainly use two different methods to polish precious metals.
For surfaces you use leather and diamantine.
You must sand the surface extensively. First with a file(if necessary), then with 240 granulated sandpaper. After that you use 1000 or 1200 granulated sandpaper to sand the surface strongly. The better you work with the 1000 granulated sandpaper is, the better your polish will be.
Take very,very little diamantine-powder and put it evenly on the leather. Rub off the sanded surface as hard as possible. The pressure is crucial.
For uneven surfaces and edges you use the polishing-steel.