once the area is cleaned in what ever fashion you want you need to protect the surface with a
zinc phosphate coating, there are other coatings out there also that do the same thing and many top shops can recommend what they prefer to use, just remember any rust is rust, many try to justify it by saying is only surface rust, the only way it will stop it is not allowing the rust to oxidize (oxygenate) by sealing the rust completely or removing completely, Paint, chrome, vinyl tops, body wraps, all let oxygen in