Dishwasher Magic safely and effectively removes lime scale, iron and food stains that can build-up inside the dishwasher with every use. By using Dishwasher Magic regularly you will extend the life of your dishwasher and improve its cleaning performance. Dishwasher Magic is the only dishwasher cleaner that kills 99.9% of bacteria like e-coli and salmonella! (gram-negative bacteria). Recommended usage: once a month to ensure optimal cleaning and prevent buildup.