After operating in an area contaminated by a hazardous substance, the personnel involved need to be able to exit the area safely. Similarly, detection instruments and samples collected during the operation need to be rendered safe so that they do not pose a threat to unprotected persons during transport and further handling. This is accomplished by decontamination of personnel and equipment. The aim of the study reported here has been to through practical tests develop a methodology of proven quality whereby personnel, equipment and samples can be decontaminated to accepted levels of residual contamination in a safe manner. The decontamination methodology is to be adapted to the needs of the Advanced Detection (AI) groups of the Swedish Civil Contingencies Agency. The methodology is to be adapted to and based on the equipment and ways of working AI applies when working in so-called hot zones. To this aim, training in sampling of staff assigned to AI at the three existing units in Sweden was carried out by FOI during 2015. The training was based upon similar training that was conducted in 2014. During the training, the way AI at the emergency services in Stockholm (Farsta), Gothenburg (Kortedala) and Malmö (Hyllie) work with sampling and the subsequent decontamination was studied. Their approaches have been compared with the way of working of the Swedish Armed Forces and with the experiences of the Swedish Defence Research Agency (FOI). Based on these comparisons, the way of working with sampling and decontamination has been harmonized. The developed, quality assured methodology, principles and guidelines have been documented in the Recommended Operating Principle; "ROP sanering Avancerad Indikering (AI)". The ROP is included in this report.