Squiby ,I'll be glad to help you with the details ,if you would like.
You will need a dremel and some soft polishing wheels ( #425)
https://www.dremel.com/en_US/products/-/show-product/tools/425-emery-impregnated-disc
Use the rotating wheel parallel to the stem length.NOT " crossing" lengthwwise -
like it "rests" at the following pic :
Do not apply excess force.Gentle moves.
Have a cup of water aside,to clean from debris and cool the stem during work.
Overall it is quite easy technique.But better practice a bit first on a scrap piece of (soft) metal ,like aluminium ,copper or better bronze.
$15 for material/tools needed & workmanship
and $15 for shipping & postage (express registered mail) .
Total $30.
A fair price ,me thinks.
Also here is a better pic that shows the real hue (under natural daylight) of the anodised Ti hammered stem :