Gyeon Q²M WaterSpot is a pre-diluted acid-based solution and should thus be used neat. For best results, wash and dry your car normally and then, working on small sections at a time (it is safe for use on all exterior surfaces), mist it on liberally, wait a few seconds and then wipe it off carefully using a PB Super Buffing Towel. Once all of the affected surfaces are treated, wash and dry your car normally again. Note that in some cases the mineral content in water spots can etch underlying bodywork and glass, meaning that a visible stain remains once the mineral content is removed. The solution to this issue is to polish the affected surfaces.