yeah ive used one before and they are brilliant the difference they make is amazing. Just make shure your car is totally washed and clean first, so theres no bits of grit or crap to get stuck in it and scratch your paintwork. Then flatten out about a third of the clay bar into a disc spray a bit of your car with the quick detailer spray and just rub it over the surface, you dont have to press down just let it glide across. Do a little bit then run your hand over the finished area and compare it to an unclayed bit and youll be amazed.