A method for removing polymer as an etching residue is described. A water activatable adhesive that, when activated, can adhere to a wearer’s skin is also deposited on at least part of the absorbent article is also described. The light reflected by the second mirror is reflected by a third mirror in a direction opposite to a direction in which the light is reflected by the quick return mirror, and is further reflected by a fourth mirror toward an eyepiece located on a back side of the body unit.