Prep work makes the paint job.
If you want to do it correctly the first time, have them sand blasted. That will remove everything, rust, oil, and loose paint off them. Then primer, paint, and clear coat for protection of the paint job.
If you want to do it the low cost way, sand-sand-sand with sand paper. If you hit bare metal you must for sure prime them before you paint them, and do not touch the bare metal with your naked hand. Oil from your skin will cause the primer or paint not to stick. If you do touch, degrease the area well, with some sort of liquid prep. such as lacquer thinner as it wont leave a film behind like brake cleaner. Brake cleaner is for cleaning brakes, not prepping for a paint job.
Have any questions, feel free to ask away. And take some pictures and show off what you have done when finished.
~F~