While it depends on the size of the vehicle being cleaned and how dirty the vehicle is, Each cloth can be used at least 50 times.
When the cloths nap is hard to the touch and appears crusted and flat it is time to replace your cloth.
KozaK auto drywash works the same on fiberglass and metal surfaces.
When used according to the instructions the KozaK drywash cloth is safe to use on any car finish.