Sending unit's out; how do I take it apart?

[The Warden]

Okay, I've got the fuel sending unit out of the car...pretty easy.

Now, for the million-dollar question How do you get the big metal tube out? I'm referring to the one that houses the float itself. I want to clean up the contacts while I have the car down.

I've done a search, and other posts refer to a small nut on "the bottom" of the tube, but I can't find it. I've got a plastic sheath around a metal part which I would assume is where the fuel drains out, at the very bottom. On the top, I've got the 3 electrical contacts, and a plastic dowel and nothing else.

How does this work? Thanks in advance!