First, fill a bucket with water and add some dishwashing liquid into it. Take a piece of cloth, wet it in the water and clean a window with it. Wait few minutes until the windowpane dries and then spray its surface with liquid used to clean windowpanes. Use a dry piece of cloth and clean the window by quickly rubbing the cloth against the surface of the windowpane. Next, take another piece of dry cloth and use it to polish the pane. Check whether the windowpane shines and if it is not perfectly clean, spray it with the liquid and repeat the procedure.