For bugs, I just use really )))HOT((( water. As hot as you can stand.
For tar, I just use some gasoline on a rag. And it won't hurt the paint as long as you're washing the vehicle soon, or wash down the treated area. And as long as the gas/on paint isn't baking in the sun with a full swath(((SPLAHHH))) of gas laying all over the paint. Even at $3/gal, gas is cheaper than B&T remover.