Sorry to hear about your prelude, take it to a car wash and get it cleaned, warm soapy water is the best way. Believe me a paintballed for a good 5 years. Kids like that ruin the sport.
True story on that matter. Me and my friends were hanging out at my place a few years back. We heard paintball guns (markers is the technical) and we got excited cause we recognized it. Went outside to see them shooting our street signs and babbling about doing cars, with a $30 walmart gun. So we had some air and paint left (like we always do), came out and shot one shot hitting the kid dead on in the back. Now my gun being a 2k3 vert autococker (when mechanical autocockers were still cool) with an Smart Parts 14" barrel, compressed air and upgrades easily hurt more than his crap could at that distance.
We told them the next shot will be in the forehead and if we ever catch you bastards doing this crap again ESPECIALLY without masks we will call the cops then whoop your ass once they leave. Then the kids started admiring my marker, asking advice about playing and told me "it hurt more than he thought". All in all no one got hurt, they learned a lesson about respect and paintball lol. True story.