Peter, I've posted this before but I think it's worth posting again in case you want to try it. Sand blast using plain old Lowes builders sand. Afterwards mix up equal parts of beeswax, Johnsons paste wax, Linseed oil, Turpentine, and put in a spoonful or two of Japan drier. Heat the whole thing in a double boiler or use a heat gun and stir. Let it cool. Smear the blade with the stuff and let dry for a couple of hours. Buff with a soft rag.
What you get is a grey, non-reflective finish that is smoothe to the touch. What you don't get is rust. Try it on some scrap and see what you think.
You can change the solvent for other things as well. Acetone works well for polished steel.
Just cap the jar and it will store well.
The above formula also works on wood for an antique finish. Takes 4 or 5 coats but is beautiful on figured wood.