Abstract: A document of value is provided comprising a soil or wear level test feature for determining whether the document of value is soiled. The soil or wear level test feature comprises: a reference area comprising a first region of the document; and a measurement area comprising a second region of the document. The reflectance of the measurement area is affected differently by the presence of soil or wear to that of the reference area, such that the difference in reflectance between the reference area and the measurement area provides an indicator of the degree of soiling or of the degree of wear of the document of value. Also provided is a method for detecting the soil or wear level of a document of value.