Clearcoat that is dull can be polished back to a nice shine in most cases. A polish of the correct grit and type is needed. This one works well for us, others are available. 

 [![Polish][1]][1]

A "dual Action" polisher is the easiest tool to use. Polishing can be done by hand with much time and effort. A single action rotary buffer tool can be used but needs an experienced hand to avoid damaging the paint.

[![Polisher][2]][2]

First clean the whole vehicle to remove all contaminates. High pressure water is used to clear all grit from crevices. Follow the instructions for the chosen polish; usually this involves polishing one small area at a time. Clean off all the dried polish.  As long as the paint is intact this is all that will be needed. Applying new clearcoat by itself is not a common repair. 

  [1]: https://i.sstatic.net/hVf0B.gif
  [2]: https://i.sstatic.net/MolS4.gif
  [3]: http://www.pinnaclewax.com/pc7424.html