Help! My Challenger got some sort of overspray on the front and front left fender. I'm not sure what it is, but I think it may have been concrete spray. Earlier this week on the way to work there was a place where they were putting down concrete and I remember driving through some water right in that area. I washed the car last night and noticed it. Today I was off and I tried a clay bar, cleaner wax and bug/tar removal. Interesting part is that if I take my fingernail I can scrape it off. I can't tell if it is concrete or paint. It is grayish in color although a light gray. Suggestions on how I can safely get this off my Challenger?