I made a discovery a trip or two ago that maybe others know of but was new to me. Motel soaps make the best windshield cleaner I've found, it will also work on headlights and other front end parts. The soap is gentle to the parts and so easy to use, especially the soft slimy piece left on the sink when you check out. After our last trip I took a couple of the unused bars and got the wife to donate a piece worn out pantyhose to hold them. Now I get both the soap and the front end parts wet and almost just wipe the bug remains away, then rinse or wet towel the mess off. I'm sure any bar soap would work but motel soaps will just end up in the trash anyway.