Reading this reminded me of an "incident" I had in Portugal last year with a hire car (Hertz)...

Roads in Northern Portugal seem to have a habit of going from three lane motorway to donkey track without warning. As a result, I managed to put a scratch in the side of the car, about 12 inches long. The car was a metailic black, and the scratch went through to the white undercoat, so it was very visible

A flash of genius found me in a Portugese stationers, looking for a black permanent marker, and ten minutes of colouring in later, the car was as good as new - or at the very least, good enough for Hertz not to notice