I have owned Black and Dark colored New Cars in the past. I do not care how careful you are either handling the car, washing, driving, etc. I was never able, in my ultra anal life, to keep those cars looking brand new. It drove myself INSANE. I LOVE A BLACK CAR, looks like a liquid finish when new. My solution to my problem, I have purchased Silver or White cars ONLY, since 1996. Done Deal!
Maybe that is not a realistic goal for some but I can bet others on this site wanted the dark colors but got a light color because of the reasons you speak of.
Use cotton gloves to close the trunk. They are used to handle photographic negatives. Keeps the grease off and WILL NOT SCRATCH. Of course anything will scratch if you run your finger over a very dirty surface.
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