A washer holding device for temporarily retaining nonmagnetic washers being applied to a building material surface with a fastener gun comprises an arm for affixing the washer holding device to a fastener gun and a washer receptacle joined to the arm. The washer receptacle includes a contacting end, a washer receiving cavity, and a central aperture, with the contacting end defining a distal end of the washer holding device and the cavity sized to receive a nonmagnetic washer such that the washer is temporarily retained within the cavity via a friction fit. An embodiment may include a shoulder, such as an annular flange, recessed from the contacting end, with the shoulder adapted to contact the surface of a deformable building material to limit the depression of the washer receptacle into the building material. The arm may be of various configurations for use with different style fastener guns.