Use water and paper towel to clean residue and fine articles on the glass surface. * Choose the pink diamond lapping film and use it in the same way as the green one. The grinding zone by the pink diamond lapping film should cover the whole zone grinded by the green diamond lapping firm. When the trace of the green diamond lapping film is completely removed, clean the glass surface and check it to make sure it is ok. * Choose the blue diamond lapping film and use it in the same way as the green one and the pink one. The grinding zone by the blue plate should cover the whole zone grinded by the pink plate. * Finally, use the orange diamond lapping film to do the grinding. The grinded zone should be looked semi-transparent and scratches are all gone. * Now let's start the final polishing.