An older home with metal boxes that don't have threaded grounding holes has both top & bottom cable clamps utilized. The grounds are twisted together, cut very short and are not connected to the box. I may be able to use crimp sleeves to install a ground pigtail. If I connect the pigtail to a self-grounding receptacle, will the grounded receptacle effectively ground the box, or does the concept of self-grounding receptacles only work the reverse way
(grounded boxes don't require pigtail)?