If it's really bad and rough to the touch, it'll need to be wet-sanded, buffed with an electric buffer and rubbing compound, then finished with a quality wax coat. If it's just faded, buffer and rubbing compound alone will bring it back. Reapply wax every few months to keep it smooth and shiny. I did this for my last two oxidized boats (I was a broke college kid and could only afford the rougher looking rigs) and restored them nicely. Gotta keep wax on them though.