Never use an abrasive cleaner on the hardware. Many of the components are coated with a clear lacquer that will be irreparably damaged if subjected to harsh, abrasive chemicals. Advise your customer to use "Repellant Wash" on hardware and door. Spray the hardware and glass and dry with a clean, soft towel on a regular basis. If mineral deposits build-up, mix a couple of drops of a mild liquid soap (such as Ivory or a similar product) into a cup of warm water or "Amaz" can be used to remove the water spots. Clean the hardware using a soft non-abrasive cloth. Then rinse thoroughly and dry with a soft towel.