Zep Acidic Toilet Bowl Cleaner quickly removes rust, dissolves organic stains and cleans hard water residue from toilets and urinals. Its powerful 10 percent acid gel formula enables the cleaner to tackle even the most stubborn of stains. The thick gel clings to vertical surfaces, while its squirt top makes for an easy under-the-rim application. The formula's fresh wintergreen scent removes the harsh odor associated with most cleansers.