I used acetone to do this and it was great. Wear rubber gloves because acetone strips all the oils out of your hands.
I spent a year in Florida on a work assignment, and had my windows tinted while I was down there. When I moved back to Maryland, a Montgomery County cop pulled me over (really?) to ticket me for the tinting. It wasn’t that dark, and in fact I paid a premium for tinting that would screen out heat without reducing visibility very much.