any surface found in a bathroom examples include glass ceramic porcelain tile acrylic or fiberglass if it is desired to determine the residue left on a particular substrate that substrate can be used for comparing the residue left by different compositions any type of substrate can be used for comparative purposes when selecting a substrate all of the surfaces should be the same because all surfaces will be immersed in the composition to the same depth for testing tile for example typically has a glazed finish on one surface and clay on an opposite surface tile should be provided that has the same glazed finish on all surfaces for convenience glass laboratory slides can be selected as the substrate optionally the substrate can be rinsed prior to use to provide a clean substrate in one embodiment the rinsing is done with each of the following materials in succession tap water deionized water generally less than about 1 u03bcsem 200 proof ethanol and reagent grade acetone after rinsing the substrate is allowed to dry optionally the substrate can be dried between each rinse material the water hardness of water used to dilute the composition can be selected to be any desired hardness by selecting different water hardness the effect of water hardness on the deposition onto substrates can be measured mixing can be done with any type of mixer that can mix the contents of the container size selected in some embodiments the mixer can be.