Heard this idea, and was skeptical, but I tested it and it appears to genuinely work!
I sprayed the front of my van with a hose to loosen the dead carcasses as much as possible, leaving just the juice, random parts and stains behind. I then cleaned half the hood with a sponge and soap to see how difficult it would be to remove the bugs...and it was nearly impossible, and required a tremendous amount of scrubbing and effort.
I used a Bounce dryer sheet to clean the other half. Everything was removed instantly!
Spray the front of the car and wet it thoroughly, then take a dry Bounce dryer sheet and start rubbing the stains lightly, then add pressure as necessary. I would recommend rinsing immediately, especially on black plastic pieces, then washing with clean soap and water to remove the fabric softener residue.
I got every spot off the front of my van in minutes with no effort.