What wax is the best to use on a car to bring the color back into the car if it is a older car?

Waxing will not bring back the colour on an older car if there is oxidization. Oxidization needs to be removed with a suitable polish, then wax can be applied to protect the fresh paint surface. VaporWax is a non abrasive acrylic conditioner that will remove oxidation from automotive paint on contact. Safe for all acrylic paint and clear coat.