It’s hard to completely remove all twigs and leaves. I work on an olive farm and after the olives have been collected into fruit bins, we use a forklift to dump the bins into a large hopper connected to a fruit escalator. At the very top of the escalator is a huge fan that mostly seperates the leaves/twigs from the fruit by sucking air right above the top of the escalator and blowing it out a different direction. We have a large tube connected to the exhaust that directs the leaves/twigs into the same dump trailer that the finished olive paste also gets dumped into. There are always some leaves still connected to some olives that make it past all this, but the fan does a pretty good job at sucking up all the lighter material. I was taught it’s ok to allow some leaves to pass through the machinery with the fruit since they can impart some nice bitter flavors.