Provided are devices and methods for quantifying a surface's cleanliness relative to a contaminant. Such devices and methods may comprise and/or use a source of interrogating radiation to which the contaminant is responsive, a means for directing the interrogating radiation, a detector, and an analyzer. Radiation emitted from the source is directed by the radiation means toward an article having the surface or comprising a surface cleaner that may hold the contaminant. The detector detects radiation from the article produced in response to the interrogating radiation by the contaminant, e.g., fluorescent or phosphorescent radiation, and generate a corresponding signal that is compared by the analyzer relative to an electronic standard that corresponds to the surface in an acceptably clean state so as to quantify the surface's cleanliness.