A composition may include, in dry form: (a) nigrosin; (b) wheat flour; and (c) whole egg. Such compositions may be used for production of test soil for assessment of the cleaning action of cleaning devices. Methods of producing a test soil for assessment of the cleaning action of cleaning devices for cleaning of vessels for human egesta, e.g., of washer-disinfectors, including dissolving the composition in an aqueous medium. A test soil may include the constituents of the composition in an aqueous medium, and such soils may be used for assessment of the cleaning action of cleaning devices. A method may assess the cleaning action of cleaning devices for cleaning of vessels for human egesta.