Use Poorboys world Professional Polish with a good microfiber/pad cloth. It's a cleaner without abrasives. I use it for getting off (nasty)stains, but also dead bugs, birdpoop etc. Here's the link:
http://www.poorboysworld.com/professional-polish.htm
Make sure the cloth you use to rub the stain with doesn't scratch the car, otherwise you need to use a scratchremover afterwards. I never use cotton or woollen cloths anymore, as they
do scratch, eventhough the manufacturer claims they don't. Of course I have a black car....which you can scratch just by looking at it too long

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