We just got home from a 4 week trip out west. While we were out there, Montana was working on I 90. They had it ground down and had put tar on top of the small gravel. It is all over the bottom of my 5th wheel on the fiberglass. I know they make products that take the tar off cars, but it is harsh and sometimes takes the paint off. I was wondering if anyone had used a product that removes tar from fiberglass. Any help would be appreciated since my 5th wheel is nasty.