Turns out that this crayon stuff is very tough, so
- Tar remover does not work
- Cleaner wax does not work
However, Isopropyl rubbing alcohol dissolved it instantly, and the white towels I used to wipe the stuff away had no black markings on it, i.e. besides absorbing the dye and some surrounding dirt, the paint was not coming off.
Thanks for all the help, everybody! And there are some great tips that came along the way and that I will remember!
