A magnet fixing device in a cleaning tool (1) for use in a borehole where the cleaning tool (1) is externally provided with at least one projection (8) and at least two recesses (6) and where at least one magnet (12) is disposed in the projection (8), as the magnetic field from the at least one magnet (12) is active in that it is arranged to at least attract a magnet sensitive material (20) into a recess (6) or hold the material (20) in the recess (6), and where the magnet (12) runs through the projection (8), whereby the one magnet (12) pole is active in a first recess (6) while the other magnet (12) pole is active in a second recess (6).