Some years ago there were reports of cars parked near rail lines, particularly where the tracks were running on viaducts, suffering paint damage from the fallout from cast iron brake shoes. Not sure whether trains still use cast iron shoes but the recommendation at the time was a week warm water solution of disolved oxalis acid crystals .
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Try living near a steel works. Everything covered in abrasive red grit. A mate used silicone grease on spark plug leads - was arcing a treat! Lot better now but still a problem in port talbot.