Chemicals in local water supplies can be damaging and corrosive to metals. Almost all Glass cleaners contain ammonia which is corrosive to metals used in stained glass. So here is a great answer to "How to Care for Stained Glass". Formulated to neutralize any remaining acids and to eliminate "mold" which may apprear on stained glass for various reasons. Streak-free shine on glass! Spray on, wipe off with dry cloth or paper towel. Spray Bottle is 16 fl oz.