A method of forming a water soluble biocidal film on a solid household, food preparation, or medical surface, which protects the solid surface against reinfection by microorganisms, includes providing a liquid biocidal composition comprised of, based on total weight of the liquid biocidal composition from 0. The air deflector includes a top surface, a front portion, an outer side portion, an inner side portion and a rear wing portion. This new and distinct variety has shown to be uniform and stable in the resulting generations from asexual propagation. In one embodiment the metal is lead or lead alloy and the method relates to the forming of a lead or lead alloy anode. The locking counterpart element is adapted to move the plug-in unit to a plugged-in position, and the releasing counterpart element is adapted to move the plug-in unit to an outer releasing position. The first and second sealing caps respectively close the first and second vent holes, when the revolving member is mounted at the closing position.