Well, I will probably get a little heat from this suggestion, but try a LITTLE WD-40. I used it to get all the bugs off of my '00 GT 'Vert front bumper a few years ago. I drove into a swarm of them who were trying to escape the fires in Florida. (I was on the Interstate.)
I felt like I was in a war movie! All of a sudden they were there!
Anywho, WD-40 worked for me. (Caution: Use at your own risk!)
Just my 2c...
StangVert00