Trailer door oxidizing

[Winged Wheel]

I purchased a trailer last summer from another bbq competitior. It is about 5-6 years old and used to have a wrap on it. I noticed the door was starting to oxidize or something this spring. Anyone know what is causing this and how to fix/prevent it from getting worse?

[Untraceable]

I think what's going on is between the paint and the surface. Cant imagine there being much you can do about it

[Zak]

Steel or aluminum?

[Winged Wheel]

i believe it is aluminum

[kls44]

Looks like its aluminum's equivilent to steel's rust. Cut, sand, grind out the oxidation and treat with an aluminum annodizer, get it at an automotive paint store. Probably will need to patch the holes.