Moro blade. derust or etching

[fernando]

I have already shown this piece in the Forum. A Moro spearhead fitted with a dagger handle. Most probably adapted rather long ago, judging by the aspect of the brass collar and the hand turned wood grip, having just now come apart, destroyed by worms.
Could i say this is a 19th century blade ? and probably also the handle ?
My other and basic question is that i couldn't get it cleaner than what can be seen in the pictures, after enduring some tryals with WD-40 and steel wool.
Should i try and remove the remaining hard dark crust, still abundant at the edge concavities ? and should it be just a derusting or will it call for an etching ? any forging activity possible to show up in this type of blades ? is the vinegar treatment equal for either purposes, only depending in timings and procedures ?
I would be much obliged for coments and teachings.
fernando