They're clear coated if they didn't go dull all over in the first 6 months. Even more so confident they're cleared if you drop that in a Canadian winter!
If the clear cost has gone "hazy", it's strip, polish and reapply clear.
The first two are easily done at home. The reapply is not.....
You
MAY be able to get away with a bit of light wet sanding with a 1500-2000 grit and then compounding/polish like you would a regular paint finish.
Be careful you don't go through the clear though (stay super super SUPER light sanding the edges/corners) or you' ll be back to strip, polish and reapply clear as above....
Last option (and the least attractive) is to strip and polish and not clear it again. It means you'll be polishing them up again every few months if you like 'em shiny!
One thing I would suggest first is that you give "Autosol" a try. It is a polish available at crappy tire (and other places) that is a metal polish. It has a light abrasive in the cream and just may strip enough clear to clean it up without having to go the full "recoat" route. I've always had good luck with it.
Good luck