Plating and polishing significantly reduces the amount of variations
in the surface of the mold. Take a look at the mold you have now under
a magnifying glass.....the higher the power the better and compare
that surface with one that has been plated and polished. The
difference will amaze you. You can simply polish out an aluminum mold,
but the surface will start to corrode almost imediately and will not
tolerate being touched by anything that is hard without damage.

HTH...

Craig C.