My suggestion is to find a company that anodises aluminium components.
I have done just that in Australia with stunning results.
So there may be hope yet for those scratched and tarnished parts.
I have been trying to find a company in the UK that does anodising for years with no luck... Could you post a picture of the bits you have had done, really interested to see the results
I went through the same quest in this country some time ago. I was told that the type of bright anodizing we are talking of is no longer possible here due to the process using cyanide or some other toxic component that I cant remember. Could be that our Australian friends are not so obstructed by h&s.