Antique Valve Covers

[bustingear]

I found some great 60's style, finned, billet valve covers at the swap meet and I am trying to clean them up.
I have used 1500 grit sandpaper, Eagle wad polish and their aluminum paste, White Diamonds, emery stick on the wheel and still I cant move the grey ghosts away. I think they have been sitting some time. Does anyone have a solution that works?

[Crestliner]

Might bead blast them and resand then polish.

[Roadsters.com]

Post a picture of them so we know exactly what valve covers you're talking about. That will determine whether you have something old that was sand-cast, or something recent that was die-cast.

The marks you're referring to could be stains that can be removed with coarser abrasives than you've been using; but they could also be imperfections as a result of being cast with metal that contained some impurities.

Post the picture, and then I can offer some thoughts on what to do to fix them.

Dave
http://www.roadsters.com/