Just a quick question out of curiosity, what material are these cast from? 

My first thought was Aluminium / cast alloy but happy to stand corrected.

Can these be polished, or do you have to spend $ on chrome ones instead?

Cheers.

I would guess magnesium alloy. This was/is a common material bike parts are made from but i could be wrong.

Edit, May be even just auminium alloy.

Edit 2, i wouldnt think that they would polish up very good thats why they are chromed or painted in the first place.

Cast alloy

I sell New Chrome Hand Controls for $280.00 and $90.00 for Chrome Switches with wiring loom, Not worth the trouble of getting them Chromed or Polished