get it off what? glass? paint? laquer thinner or reducer for paint works along with some scrubbing, or very fine steel wool or razor blade. to get it off paint i would think the only way is to give it a quick wetsand and buff.
caly bar will probably do it, if not even a heavy to mild cut would probably do it for you, i would do wet sand as a last resort just for the sake of time and amount of work.
I got some on one of my cars while I had the garage open and painted another car for a friend of mine. it was just clear coat over spray. a very light dusting too. just felt like the car wasn't waxed but you could see it at all. I took a mild buffing compound and buffer and with ing about 30 minutes had the car smooth again.