I did car detailing and that's pretty cheap for sap and stains. I remember doing someone's car like that and I was cursing the whole way (since I was hourly).

That is definitely somehting you should prevent in the future by buying a car cover. Or parking someplace else if you can. If I had a choice between parking under a tree or out in the bright sun - I would do bright sun. Since the paint can handle sunlight if you have a clear coat and take care of the outside at least twice a year.