Systems and methods for detecting presence of a thing, the thing treated with a descenter, one method including in an area in which it is possible that a thing treated with a descenter is present, using a detector to detect a descenter level in the area, producing a detected descenter level, comparing the detected descenter level to a normal descenter level for the area, determining that the detected descenter level is different from the normal descenter level, said determining indicating the possible presence of a thing treated with a descenter； and using a trained service animal to facilitate such a method.
