A device in connection with a separator for cleaning or reaming such a separator. The separator includes a tank or a body (2) with an inlet and at least one outlet (5, 6). A transport pipeline (3) is connected to the inlet for the supply of fluid that is to be separated in the separator. The transport pipeline (3) extends from the inlet through the separator body (2). Part (6) of the line that is located inside the separator body (2) is provided with perforations or slits (7) so that fluid that arrives in the transport pipeline (3) flows into the tank through the perforations/slits (7). Mechanical equipment for cleaning the transport pipeline (3) is designed to be sent from a magazine through the separator body (2) and on via a pipe loop back to the magazine.