When I wash the Prius, no matter how hard I scrub, I hate it when I find bits of bug guts that DO NOT come off and leave behind a visible residue. Even with hot water and a decent detergent. I want something that will cut through this crud but NOT damage the paint/clearcoat. I've used things like WD-40 when it's oil/tar related, but bug guts seem to bond to the paint over time.
Bugs and bird poop really are hard on a paint finish. When I got me car, I immediately waxed it with a clear coat wax. Because I have gone thru this before and wished I had done it when I first got other cars. Mendel Leisk's example is good, but just make sure to wax the area afterwards. A good wax will keep the stuff from penetrating the clear coat.
I've used Turtle Wax Bug and Tar Remover as needed on the Prius w/no problems or issues w/the clear coat. It's specifically safe for Clear Coat..
