A cleaning system for cleaning a valve seat, where the valve seat is formed of at least one gasket for sealing between a housing and a stem, preferably for a double seat valve and where at least one guide band is centering the stem in the housing, where the stem has a cut out, allowing a cleaning liquid to flush the seat, when the stem is in a cleaning position, and where the guide band is still centering the stem while in the cleaning position. By putting the stem into a cleaning position, the cut out in the stem is positioned in the area of the gasket and thereby allowing the cleaning liquid to pass the gasket and the guide band via a small gap between the guide band and the stem itself. This way the seat is flushed with cleaning liquid and is thereby cleaned.