The article is mute on one key element: how do the dissolved components get back across the blood-brain barrier? I can see how it could dissolve and its remnan

The article is mute on one key element: how do the dissolved components get back across the blood-brain barrier? I can see how it could dissolve and its remnants be carried out via the bloodstream and/or lymph system if it was elsewhere in the body... but how does it get out of the brain?