Some people, presumably kids, spray painted my windows and other parts of my car the other weekend. I took the critical area's (the windows) off with a razor blade paint scraper. How can I get the rest of the spray paint off without damaging the cars actual paint?
The first thing that I usually try in situations like this is some cleaner wax (e.g., some Zymol - it's cheap, cheerful and smells nice):
I'm pretty pleased with the procedure that I outlined in the attached "door ding" answer. The most important point, though, is that patience is key. You're almost certainly super annoyed at this situation (I'm annoyed and it's not even my car!) but you're going to have to accept that slow and careful progress is much better than making the problem worse.
A professional quality re-finish would mean stripping the affected paint work back to bare metal and a re-spray, but not always. Firstly, try on a small area of the effected paint work an application of regular domestic oven cleaner. Leave it on for only the time it takes to soften the spray paint and rinse off the emulsion produced straight away with clean water. Use a pair of protective gloves to keep the oven cleaner off of your hands. With the spray paint removed polish the paint work of the car with car polish. This works on most car finishes.
I have personally used brake parts cleaner. It shouldn't harm dried clear coat factory paint. Any other paint will be annihilated, though. Alternatives are acetone, paint thinner, gasoline. I'd use extra care with those 3.
(some other people with personal experience using these)