Warranty Booklet| page 14, Items Which Are Not Covered“DAMAGE FROM THE ENVIRONMENT: Parts made from cloth or leather (upholstery, convertible tops, trim items), wood, paint or chrome which have been affected by airborne fallout, such as chemical and tree sap, or by road salt, hail, windstorm or other environmental factors are not covered by this warranty”

Owners Manual| page 156, Care“Cleaning the paintwork:
Remove dirt immediately, where possible, while avoiding rubbing too hard.
Soak insect remains with insect remover and rinse off the treated areas afterwards.
Soak bird droppings with water and rinse off the treated areas afterwards.
Remove coolant, brake fluid, tree resin, oils, fuels and greases by rubbing gently with a cloth soaked in petroleum ether or lighter fluid.
Use tar remover to remove tar stains.
Use silicone remover to remove wax 

The following cannot always be completely repaired:
corrosive deposits
areas affected by corrosion
damage caused by inadequate care”