Got insurance, maybe a lawyer?? Sounds like they acid washed the white skin......

A painted aluminum trailer should only be commercially washed with a citrus product. Continued acid washing will damage the very thin paint coating, that is roll coated before the trailer manufacturer takes delivery of the product. As the paint is being damaged, the first thing you will notice is an overall dulling of the finish. This is a result of the surface being eroded by the acid and damaged by UV rays. Originally the paint was applied with heat, resulting in a smooth, glossy finish. When the coating is destroyed, the bare aluminum will eventually be revealed.

Before any paint is applied to the aluminum, the metal is chemically dipped to remove any contaminants that might prevent a proper application. This process also removes the oxidation from the metal. When the bare aluminum is later exposed to air, it will again oxidize, naturally creating the dull coating that protects the metal.

Unfortunately your only recourse is to repaint the trailer.