1Start by removing the part that needs to be painted. (You can also tape around it, but be careful about overs pray) 2Sand the part with the 300 grit sand paper until the surface is a little rough....
Take it to a body shop and have it repainted - aerosol cans are not capable of spraying the same kind of paint as a professional and even if they could the propellant and method of application that...
use rubbing compound from your local auto store. theres different strengths so be carfull. this stuff is also good for cleaning up the paint by taking out sratches and removing wax. use elbow grease...