Dagger after cleaning
 

After some cleaning, I was hoping to remove the black spots...

Dagger
 

I have cleaned it with oil. Is there any other way to clean in order to remove the black spots?

It's beautiful, just a little oil to keep it that way.
Rich

Any further and you risk removing the patina and the pattern. You have a very nice piece there .

agree, nice piece. any further cleaning agressive enough to remove the spots may leave scratches and degrade the nice wootz watered steel patterning. if you can't get them off by rubbing with a wood stick or the edge of a copper coin, best leave them. if you are really handy, or a dentist, pricking off any crustycrusty red scale with a dental pick under a microscope might work, but i wouldn't try it. the knife is too nice to chance messing it up. lots of olive oil and an old toothbrush (without toothpaste) repeated over time may lift, loosen & remove a bit more. in some climates the olive oil, if left on may go rancid. i use ballistol on just about everything for storage.

black rust and black patina is good, red rust is cancerous and bad.

Yes black is stabilized, red is active and eats through. Your blade looks fine as it is now...........

Very nice, it has a qama type hilt and a jambiya blade. Is there a scabbard?

Dagger
 

Dagger scabbard