Was inspecting the front axle actuator on my Blazer and found this piece lying under the actuator, couldn't tell what it came off of. It is cylindrical, enclosed at one end, open at the other and has a pentagonal hole in the closed end. Slightly larger than my thumb. Any ideas what it is?

 

not sure on this one. Almost looks like the outer shell of those things that you clean battery terminals with.

 

Hadn't seen one so looked it up, that looks like what it is. Someone must have dropped it down there at some point. Thanks

 

battery terminal cleaner cap.