Used MEK on thousand and thousands of cars, it doesn't hurt any car paint, but it is great for overspray. Don't put it on rubber, leather or plastic. We got it from the Eagle One and Meguiars rep, and those are two huge companies and they sell to thousands of carwashes, so it's probably used in the millions of times in the carwash industry. I've used clay bars too, that works too but you will be at it for hours. Most people that tried the orange hand degreaser are the ones that brought their paint in destroyed. Pumice is like 800 grit sandpaper. I could get the scratches out after people used pumice, but it takes hours and good foam buffing pads. Wax will work if the paint isn't stuck good and there isn't alot of it, but if you are using a machine the paint that comes off (loose overspray) will swirl the paint badly. I used to wash 60,000 cars a year, detailing maybe 20-30 a day and made 7 figures doing it, so I'm not saying maybe MEK works, I owned the carwash for 11 years and used MEK every day. Including multiple times on my own cars, which weren't new, and there was no damage at all. Quite literally, Eagle One and Meguiars sell it (or at least they did 11 years back when I had the carwash) in an aerosol can that is labeled "Clear Coat Safe OverSpray Removal".
There was one year where it became popular for kids (Kingwood High School) to spray paint cuss words on each others cars. For a few weeks there, we were de-spray painting cars, maybe 10 per week. And one kid brought in a car with "female dog" written on the side in house paint. She had used a scrubby pad for one side, and scratched the paint crazy bad, and we literally wiped off the paint on the other side in less than 5 minutes with no paint damage at all. I then I spent 4 hours fixing the other side the best I could. It was a black car too, those are the hardest. And she kept coming in for years after that and there were no side effects.
Just try a small rag with one drop of MEK, and you will be sold. Post pictures up here of the before and after to make the people that have never tried it for overspray believers.
I didn't think it was a good idea at first either until the rep for Eagle one spray painted on the side of his own car to show me....
And if you have ever been to a detailer or full service car wash, they have already put MEK on your car or boat, you just didn't know it.