bowl cleaner Blue cleans,colors,freshens and disinfects your toilet with each flush! DIRECTIONS: 1,Remove the cistern cover 2,Lift tab on the card and pull back,do not remove the special wrapping on the block as this will dissolve in the water 3,Drop the block into the water opposite the water inlet. when the color begin to fade,replace with another block. PDCB AND PHOSPHATE FREE.