bird droppings on grand prix white

Vehicle Information: Model: 911; Year: 1996; Body Type: Coupe; Total Mileage: 33,000;

I got a bird dropping today when I was driving around. I discovered it when I got home. It is on the engine cover right above the spoiler. That location gets hot with the engine. How do I completely remove the off color stain that remained after a careful wash with griots, etc.? Is there a magic solution for getting these stains out of grand prix white paint? It is barely noticeable but since I know it is there, I would like to get it off the paint. thanks Wendell