I usually cut my clay bar into 3 to 4 pieces and use them up like that. If your car is not too bad, you only need 1/4 of the clay bar. You kneed it out then use it. As it picks up contaminants, you fold it in half, kneed it out again, and repeat. After you use the clay bar for a bit, it will get to the point where you can't use it anymore. That's when you throw it out. Check out this video for the basic process, just ignore the product branding: Please wait a few seconds for Video to Load! Nice link there!! Thanks again!!!!!!! Damn this thread ... it's made me want to go and buy some clay now