That compound gets really tuff to get out after it dries dosent it. The only thing that I have found is warm water with a little soap and a soft sponge. You'll need plenty of elbow greese. I have used my finger nail sometimes on the really thick stuff. After it has soked for a wile.
Of course the best way of taking it off. Is to do it before it dries as your buffing the car. I know a little late now. Right?