From reader Snowbird:

I've gotten paint out of my husbands clothing before by spraying it with WD-40 and rubbing it in really good and washing as usual. The paint was pretty fresh when I did it though, I don't know how good it will work if the paint has been on there for awhile though. I guess its worth a try, I also use it regularly to take the paint off of my hands when I'm done painting my crafts, works great for that. Hope this helps!