“Let’s imagine a running washing machine. Let’s imagine the dirty clothes in the machine and how the liquid detergent is getting the dirt out of clothes and draining it to the waste outlet. Now imagine brain surrounded by a large pool of cleaning fluid called CSF (cerebrospinal fluid). Imagine CSF pulling the wastes from inside the brain and draining it into the blood, which routes it to the waste outlets. CSF clears waste many times faster in sleeping brain than in the waking brain.”