Or suggest a better way of achieving a frosted or satin finish?
It depends to some extent whether you have a flat surface or one
with a lot of detail. For flat surfaces, you can use the foam bars
used for buffing acrylic nails. These are available at beauty
suppliers (like for beauticians) for sure, but just ask any woman
with beautifully manicured nails or a beautician. They might be
called something different in the UK.
Another way that works is to use the scrubbie pads for scouring pots
and pans that have grit embedded in them. They come in different
colors that indicate how agressive they are, with the green ones
being the most common. Just cut several squares out the pad, about 1
inch in size (20 mm?) and stack them onto the screw part of a screw
mandrel. If you happen to know a janitor that polishes floors with a
buffing machine, you can ask them for the center cut out of the pads,
since they throw them away anyway, and you will have various pads
that will achieve a very fine texture to a deep brushed finish. Just
cut out a square and put them on a screw mandrel.
If you don’t have to worry about delicate parts or designs, you can
put the pieces in a rotary tumbler with “sharp” sand (cheap). Along
the same lines you can sandblast them if you access to that type of
If you have a lot of detail you can use 3M’s radial bristle disks
that come in a variety of grits. You can get an idea of what these
look like by going on Rio Grande’s web site, so you can match it with
something similar to a jewelry supplier in your neck of the woods.
They are also available through woodworker suppliers.
A brass brush with very fine bristles will put a very soft and
subtle satin finish on your pieces. Lubricate with some dish soap on
the brush and some water to help spread it. Think of the dish soap
and water as a lubricant.
If the pieces are flat, you can use various grades of steel wool.
Wad up a marble-sized piece in your fingers, and with a bit of
pressure, “brush” in one direction only.