If you say it is pretty oxidized, no way around not wet sanding it.

If you haven't done it before, there are some really good youtube videos on the subject matter. Watch a few to become familiar before you jump in and ruin your gelcoat.

Agree with TurbineSurgeon above to use a good quality buffer and appropriate grit.

After wet sanding, then use the father n law approved rubbing compound. I use 3M Marine Rubbing Compound followed by Presta Ultra Polish to remove the minor surface imperfections, then I use Collinite #925 Fiberglass wax for bright shine. There are a multitude of products you can use to achieve the same results, but the four steps remain the same...wet sand, compound, polish, and wax.