to wipe three times, even if one uses only the different edges of a single stone. If the area is not yet clean, further wiping until complete removal of the impurity becomes obligatory. It is recommended to keep the number of wipes odd and to dedicate a separate stone to each spot—though another opinion holds that the wipes should be divided between the two sides and the middle. It is also sunnah to perform the cleansing with one’s left hand. According to the sounder view, no istinjāʾ is required for worms or for hard droppings that leave no residue.