Soap and water? If that don't work try spraying some spray carpet cleaner on there and use a sponge with a little bit of water on it. I know it sounds crazy but it works, I got the idea from a friend who does body work. I had a tire blowout on the highway to the rubber marks right off of the paint. But it'll take the wax off to so your gonna have to wax it when your done. And if you do decide to try it don't use too much, use a little bit more each try until it comes off.
Windex with ammonia... Spray it on and let it sit for a second. The egg will start to turn white. Then just spray some more on it and whipe it off. Use some good cleaner wax and then some finish wax and you should be good to go after that.