We've just been dealing with that ourselves. We Googled the question and either Turtle Wax Bug & Tar Remover or rubbing alcohol were the top two recommendations. I didn't have any Bug & Tar Remover (though have used it in the past) but had a liter of isopropyl alcohol. It works - but I had to use clean rags and keep going over the area(s) to get the last of it off.