Magnetic handling structure comprising a retractable magnet and a probe for the manipulation of magnetic particles in biological samples and methods of handling magnetic particles in biological samples. A method for cleaning a surface of a substrate, which comprises at least the following steps and, wherein the step is carried out after carrying out the step :Step : A cleaning step of cleaning the surface of the substrate with an alkaline cleaning agent containing a completing agent, andStep : A cleaning step employing a cleaning agent having a hydrofluoric acid content C of from 0. Slider flying height data that vary inside the tracks are prerecorded in the tracks of the magnetic disk. Spacing of the diagonal line segments encodes the X-axis position of the input device relative to the encoding pad.