I've had limited success with giving blades an "Antique" look using brass oxide. It puts a layer of oxidization on steel that is similar to blueing. It isn't very uniform on steel, though. I did use it on 1095 once, though. A rather cloudy, black coating that looked pretty good on the piece. It was the shackle of a padlock.
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Oz
"When your work speaks for itself, don't interrupt."
- Henry J. Kaiser