[TheForge] How to black wroght iron finish?

[StantonMitrany]

I have an old wrought iron table base which I'd like to save in what was its
original form- black, with no apparent coating, other than what looks like
black oxide. Some of the table, though, has a slight veneer of brown rust-
probably only molecules thick.

I'd like to restore the finish so I can use the table indoors, where the
finish isn't likely to change over the decades.

I was thinking of steel brushing it wherever I can reach, and then,

-   either oiling it by a sprayer/brush with ?what kind? of oil?,

-   or spraying/brushing it with gun bluing compound,

-   or coating it with some industrial compound such as one of the chemical
finishes applied to preserve the cast iron/steel surfaces of some factory
machines,

-   or what would you suggest?

The table base is precious to me, and I'd like to do the best thing for it.

Thank you sooo much for your input!

All the best,
Stanton