I think you're right with Saka. The Kusu and Tetela have similar shaped knives, but the blades are more slender.
When I have an object that has active woodwurm, I put it into the refrigerator for a month or so. That also kills the bug
. But this is only possible with small objects.
As to plastic on African items. Look at this Luba axe. The red circles are, in my opinion, plastic (?) rings used by a plumber.
