I use it to unstick things and use as a first pass to deep clean greasy metal parts. But mostly used in context of unsticking stuck bolts or dislodging built up grime between parts. It's great at penetrating and dislodging gunk but it doesn't "stick" so it won't lube long term. It only seems like it lubes because all the built up crud is gone so it feels smoother. But to be honest, I prefer using PB Blaster whenever I need to use a WD40-like product. I find it's slightly less greasy feeling and penetrates faster/stronger.