4/0 steel wool and light oil is the time tested method for removing rust
from blued(black oxide) guns with minimum blue damage. Ask any gunsmith.

Randy


"DeepDiver" wrote in message
...
I recently acquired a face mill that has a glossy black oxide surface
finish. The mill is in excellent condition except that the previous owner
allowed it to develop some surface rust (mostly on the upper surfaces;
probably from sitting around uncovered on a shelf). The surface rust is
like freckles, with most very small, but some spots of 2-3mm dia.
Naturally, the black oxide finish on these upper surfaces (between the rust
spots) is also dull.

I was wondering if there is a way to remove the rust (or majority of rust)
without significantly damaging the black oxide. In the past, when I has
some surface rust on some black oxide impact sockets, I tried the
following:

1. Green scotchbrite and kerosene.
2. Phosphoric acid.
3. Salt & vinegar bath.

All three methods removed the black oxide as well as the rust.

How about polishing? That will also remove the black oxide, but perhaps
not as much. Or is there an easy (and inexpensive) way to renew the
finish?

Any advice would be greatly appreciated.

- Michael