[Mark Walker]

Arizona shouldn't allow much opportunity for corrosion with the dry atmosphere.
If you are talking about mere"discoloration" rather than actual "corrosion- pitting of the surface", a wadding polish called "Never Dull" will work very well.
Surface pitting is another story and will require abrasive compounds and power tools. Take your time and be gentle of hand.

 

[Mark Walker]

You should be able to pick "Never Dull" up at an auto parts supply (Pep Boy's, etc.). It should easily do the trick.