Take with a large grain of salt.
I had road construction on the only road leaving my neighborhood for the whole summer when I first got my Duc.
I had some good luck with simple green on some things. But I had to go to a Bug & Tar remover for some others. I was very careful with it, but it did the trick without damage or blemish.
Try a small amount in a very inconspicuous area first, of course, I am
by no means an authority on such matters.