Grinding in the restoration process is the method by which the floor is sanded by means of abrasives (diamond discs) to remove large amounts of material. This process is usually beneficial when stone tiles have lippage (uneven tiles). It is usually recommended when deep stains and scratches occur or when one needs a totally flat, seamless finish to their floor. During restoration. wet or dry grinding can be employed depending on the material being worked and the physical constraints applied to some areas where the removal of slurry is a problem.