a cleaning method for a filter testing device including switching devices , external connections and internal volumes that can come into contact with a fluid from a filter device that is to be tested . the cleaning method involves the steps of : selecting one or more internal volumes to be cleaned , cleaning the selected internal volumes with a cleaning fluid by correspondingly switching the switching devices , and removing the cleaning fluid contained in the internal volumes from the internal volumes . also a computer program product with program parts for implementing the method of the invention or a preferred embodiment thereof , and a filter testing device adapted to be cleaned by the method of the invention .