• Best For: Neglected grout, tile and stone where other cleaners have failed, with years of hard water deposits, soap scum or efflorescence.
• Highlight: Its proprietary organic salt is described as twice as effective as phosphoric acid at dissolving calcium carbonate, without the unpleasant fumes.
• Expert Note: Viper Renew removes a very thin layer of grout along with the deposits, so keep a gallon on hand for the jobs where regular cleaners will not budge the soil.