I think you could accomplish most of this idea by using colored sponges from the store, then cutting them in specific shapes based on your need.

Industry wide, it might be difficult to develop a color-code that would apply to a wide enough variety of situations to be useful. On the other hand, if they sold a bag of different colors, then had a list of suggested color-coding on it, that could serve as a base for your own planning.

I think it would work very well; in fact each different sponge could be sold separately each with his own label. Not only could they be colour coded but also could have slightly different textures depending on it’s use. You could have a whole range labeled in this way....sponges, cloths etc... This idea, as first suggested, almost follows on from current trends. For example crockery labeled with types of food depending on their individual use.

One way to solve the problem would be to have the sponges imprinted with the label indicating the use. Or, it could be done whimsically, for example, imprintation with images of dogs, kitchen sink, tools, etc. - Mariette Wharton