need suggestions

Looks like oxidation. Get some aluminum polish and try to ge it cleaned up.

 

It looks like some oxidation to the aluminum. It is just a naked finish with no clear coat on top. This is wHat i would do;

1. Tape off the area around the badge to protect the red wrinkle coat.
2. Use and aluminum polish ( mothers, mequires, zymoil ) with a cloth to
polish each letter.
3. If the staining is too deep you can wet sand it with 800-1000 grit, using the paper on a block to keep the surface level. Then go back over the area with the polish.

optional.:
..Once you polish it to your liking I would clean the area with a de-greaser and dry throughly.
take a lint free polishing cloth and spray some high-temp clear coat on it and dab it onto the letters with a few light coats.

 

Hey
That is the aluminum oxidizing. The clear coat gets chipped or cracks from the heat and the elements get under and oxidize the aluminum. The best way to correct it. You need to get very fine sand paper or emery clothe and wrap it around a small block of wood and sand the letters evenly. Then you have to clear coat them but most likely will just happen again or the best bet is to wipe it down every so often with WD-40 after you sand it down.
Melissa

 

i would not use sandpaper.

 

The oxidization has etched itself into the aluminum and a very FINE sandpaper will remove the surface corrosion and bring the shine back. Much like wet sanding a car finish when its dull or scratched. I do it all the time, especially when I do a major and repaint the valve covers. It shines better then new.
Melissa

 

Try liquid "Autosol" metal polish - gentle but effective; I live right by the ocean and use this on all sorts of polished aluminium/chrome/stainless bits.

 

Now that I think of it, you are right. A very fine, I think it's called 1000 or 1500 (or something like that) whatever is the one that bodyshops use on the clearcoat to take out blemishes.