Are you working with a separatory funnel? If not, its no problem to have that bark on the bottom, whenever you stop mixing it will settle to th bottom and you can get the top layer out.

By the way, I recommend not shaking, but rather stirring, to prevent emulsions from happening.

And cool to have you posting in the forum again

Hmmm, how fine is the powder? It might be it passes through the funnel ok (lets hope so).. IF it doesnt, you could filter it out I guess but first of all, keep it without throwing away just in case (if yield comes out bad, you can always try to do some pulls on that sediments), and secondly, be careful with filtering highly caustic solution...

Let us know how it goes!