Embodiments provide systems, methods, and masking workstations for masking a planar substrate with a shield. The shield is configured to facilitate the removal of a waste portion of masking material from a portion of a planar substrate. In some cases the shield is placed adjacent to a substrate and a masking material is applied to the substrate and at least a portion of the shield. A waste portion is separated from the masking material and the shield removes the waste portion. Embodiments can be useful for masking only a portion of a planar substrate, including glass panes and glass units, for example.