Bone grease rendering is a low-return activity well described in the ethnohistorical and ethnographic literature. However, identifying this activity in archaeological contexts is complex because diagnostic criteria are few. The goals of this article are twofold: (1) to provide new experimental data on bone grease manufacture for assemblages associated with severe fragmentation, and (2) to assess how these data can be used to make stronger inferences about skeletal fat processing in the archaeological record. The results presented here show that, despite some variation, several forms of damage appear to be diagnostic of bone grease manufacture, regardless of the degree of fragmentation. The results indicate that extensive pounding produces many fragments that can be identified as deriving from articular ends, which conflicts with the oft-cited notion that articular ends are destroyed “beyond recognition” during this activity. Consequently, assemblages with few epiphyseal remains are not consistent with bone grease rendering, assuming that the comminuted fragments were not burned or discarded off-site after boiling. Because bone grease manufacture produces many small fragments, a close analysis of the indeterminate remains is strongly recommended, as is the use of fine mesh screens (2 mm or smaller) in excavations.