Pretty much you just rub and area, then knead/fold the clay, then keep doing that until you can't knead up a "clean" spot anymore. At that time discard the claybar. The specific amount of times per use is not able to be given in a number because different surfaces have different amounts of crud on them. If you are just keeping up a nearly virgin E430's finish, then you can use it many more times than say a reconditioning or bumper-bumper overspray removal.

Hope this helps...Lee