BE CAREFULL with mineral spirits , I dont doubt what Mr Wizard posted , however I had an 88 Iroc that i used that on and un beknownst to me , the valance had been repainted not long before i bought it ,,, and it took the paint right off..
I did find something ,that works GOOD, but its tedious but fast
first make sure , the valance / nosepeice is COOL not hot , then take charcoal lighter , i bought a 99cent big bottle of always save brand , and keep it just for this , and i dampen a cloth , with just a little of it , and lightly apply it to said bug splat let it sit for just a minute or so and i find that when i come back , across it it comes RIGHT off. takes tar off even easier ,,,,,, however WIZARD is right , it does remove wax so after wiping the bug splat off you have to use soap and water to remove the charcoal lighter , then rewax.
Hope this helps
PS i use rain x on the windsheild 2 applications and bug splat ZERO on windshield!!! I re apply monthly