As mrtwowheel said.
I had to use paint stripper in mine, as the paint was so thick in places, that it would never had been good looking, if I'd just painted over. I had to apply several coats of that stuff to get all the old paint out, rinsing with pressure washer in between coats.
Be careful if using paint stripper, as some of them can damage aluminium surfaces.. I used marine kind, that is safe to use on aluminium boats.