Get them treated well with nitromours. That will strip the old paint off completely. Watch it though it burns! Then you can either prime, undercoat and top coat yourself or if you want something that is going to last and that has a flexible finish you could have it powdercoated. Personaly I would have it powdercoated, it doesn't cost much. Bob jackson cycles are very cheap, they quoted me £130 for a full frame in metallic finish and they also pick up and deliver back to you. Hope this helps.