How do you polish aluminum on big rigs?

Ok so I first started off with sanding everything down with a 400 grit sander, then I moved up to an 800 grit sander. I started my polishing with a yellow airway and brown rouge. It looks pretty good, however it's not close to being a mirror finish. I'm also getting a lot of smudging, and cant seem to get rid of it. Just for kicks, I tried the white airway buffer and the white polishing bar and it made my finish look even worse. Is the trick of the finish in the sanding? I'm also doing one of those huge grills that are put on the truck in the event a truck hits an animal. Any tips on getting to all the nooks and crannies that the buffer wheel can't get at?