I can't believe it hasn't been mentioned - SODA POP can be used to remove bug guts.
Here's a link to Readers Digest for 13 weird car cleaning tips:
13 Weird Tricks to Clean Your Car | Reader's Digest
If the bug strikes are old, spray the soda on and let is sit for a few minutes...then wash with a sponge or similar material...warm water will work best for the rinse.
If you are on the road and hit a swarm (like love bugs) you can usually find a Coke or Pepsi pretty easily for a roadside clean-up.
Of course, you will want to WASH IT ALL OFF, because the acid in the soda pop is what dissolves the bug strike, so any left over soda can leave marks - and the sugars in the soda (unless you use diet) can make things sticky, which makes the problem worse.