This publication provides information and guidance on methodologies and techniques which could be used to locate, identify and characterize disused, sealed radioactive sources on historical waste sites. The sealed and shielded nature of these sources often poses a significant challenge to their characterization and thus to the verification of historical radioactive waste inventory records. Therefore, to facilitate the safe and proper classification of such sources, this publication describes the advantages and disadvantages of a number of methods of characterization, as well as the situational applicability of each.