Originally posted by Ali Al-Chalabi
Also, another common way to warp them is too get them really hot through use and then run your car through a car wash or get water on them while you are washing the car. Rotors do not like to get wet when they are hot.
Ali is right. You can warp 'em by just taking them into a car wash especially if you live in the city where lots of braking keeps your rotors at high constant temp. Splash some water on them and voila! warped rotors. Pull over near the car wash, wait a while before going in.