If your paint is clear coated then you want to avoid a cutting agent in your polish all together as this will stuff up the clear coat.
If not I would use a mild cutting agent and the rest is elbow grease. You know how they sometimes say test it out on a small, out of sight test area. Well that would be a good idea if your going to cut it as you will soon see if it si too abrasive.
As far as brands go anything by Meguirs, Mothers and maybe even Kitten. Maybe start out with some CT-18 truck was just to roll back the years.