1. You cannot remove an oxidized appearance, and make it match the rem,ainder of the coach.
2. You can paint any part of the coach with silver or any other color paint that you wish to use.
You must use the following method, if you want the job to last.
1. Remove the plasticoat.
2. Sand into the sheetmetal with 120 to 150 grit sandpaper. Scuffing the surface will not do. IT MUST BE SANDED.
Make sure "all" the gloss is gone.
3. Wash the sanded areas down with a high quality lacquer thinner.
4. Seal any and all seams with the proper sealers.
5. Use a high quality flexible primer, and apply at least two double wet coats.
6. Let the primer out gas for a day or two
7. Wipe the primer paint to remove any dust or dirt. No need to scuff it.
8. Spray at least 3 double wet coats of a "very high" quality automotive paint.
9. Before the colored paint sets up, spray paint at least 3 double wet coats of a "very high" quality clear on top of the colored paint. Do not use plasticoat.
The above process, "IF" strickly followed will give you a finished paint job that will last at least 20 years, if you wax it once a year.
Worth it.......Only if you like quality.
Anything short of the above will provide a less than satisfactory paint job.
Keep in mind, aluminum must be painted very differently and with different primers, than steel.
And finally, DO NOT APPLY ANY ACID TO THE BARE METAL.
Because you cannot remove all traces of it, therefore it will eventually eat away at each and every rivet, creating hundreds of water leaks, guaranteed!!
And if you don't sand it, the primer will not proper adhere.
We have paint jobs out there that are over 20 years old, without any peeling, fading, or chipping. A few have been in hail storms, denting the metal, but not touching the paint.
As with anything that you want to do one time and be through with it, you must do it right. If not, leave it alone and save the time, effort and money.
And if you want the problem to go away, real cheap, just wear very dark sun glasses. You know, out of sight, out of mind.