For some time I am trying to figure out what protection is used underneath mid 90s Maseratis by the factory. It’s about the chassis itself. They all appear to have the same black thin spray being used. I doubt if it’s tectyl or dinitrol as it’s non flexible and really a thin spray. It’s almost like a thin primer being used. It’s on my Ghiblis but also noticed same on QP4. Anybody know what was used back then? I want to clean and detail the underneath and like to repair some areas where there is some light rust or damages but it needs to stay original. Any views appreciated