I would just add that if you EVER drop the clay on the ground you MUST throw it away, everything sticks to it, even if you think you have it picked off. don't chance it. Instead, tear the claybar into 1/4-1/3 peices. That way if you do drop it, you won't waste the whole bar and can just toss that peice and grab another one. Also keep kneeding it to a clean section while your using the bar. Claybars also work really well on windows too, so don't forget them while your doing the paint.