Spray a lime scale remover directly on the hard-water stains and calcium deposits that have accumulated on the powder-coated surface. You can find lime scale removers at home improvement warehouses, hardware stores and janitorial supply centers.
Wait 15 minutes for the lime scale remover to work. Wipe the remaining lime scale remover away with a soft cloth.
Rinse the powder-coated item with warm water. Use a scrubber brush to remove any remaining water stains. Continue to clean the water stains until no more remain.
Rinse the powder-coated items thoroughly. It is important to remove all the acid from the lime scale cleaner you applied.