Abstract: The present disclosure provides methods for visualizing a soiling substance on a fabric and, in some aspects, methods of quantifying the efficacy of a composition for removal of a soiling substance from a fabric. In some aspects, the disclosure provides methods for visualizing a soiling substance on a fabric which include providing a fabric that includes at least one soiling substance, applying a signaling agent to an area of the fabric that includes the at least one soiling substance, illuminating at least a portion of the area of the fabric that includes the at least one soiling substance and the signaling agent with light of a wavelength or wavelength band that is one or both of absorbed by the signaling agent or effective to cause fluorescent emission from the signaling agent, detecting one or both of an absorbance signal and an emission signal from the signaling agent when illuminated.