Removing excess paint with oils or solvents is another method that works, but often works best when the paint is fresh. Oil or wax is applied to the area and allowed to soak, then cleaned to remove damage caused by excessive spraying. This occurs when you rub one of these clay sticks onto the surface, from side to side, until the adhering contaminant wears out. In the case of over-spraying the car, this means that the clay bar will slowly wear out as you rub the clay bar over the car's paint until the paint wears off.
Mineral alcohols or petroleum jelly can shed paint stains, making them fairly easy to remove. However, this usually works best with relatively recent over-spraying. After soaking, it should be much easier to remove with clay or even an MF towel.