Decorate your car windows safely with Acrylic Paint. Lately we have seen more and more reasons to want to decorate car windows. Whether it is a drive by Happy Birthday parade or a drive by congrats to the Grad or any car parade of some sort, there are so many reasons to want to write a positive message on your car windows to cheer on your family and friends. Paint Safe for Car Windows: Did you know you can use acrylic paint to write on car windows...I sure didn't. Acrylic paint as in regular old craft paint. Just make sure