just what is getting put into gas that would peel paint better than aircraft stripper?

I was just reading a letter to a magazine editor last week where the writer was telling how he'd pulled into a town late at night, and gassed up right before turning in. He gets up the next morning to find the fuel had expanded in the hot morning, and ran out of the tank and stripped the paint off the side of his car.

I doubt this is the same car, but it looks like the same thing happened to this guy.