Does glymphatic system ejects majority of metabolic waste from brain during sleep only?

Dear Student, glymphatic System is a newly discovered system for the clearance of macroscopic waste by our nervous system. In this system, astroglial cells form a unique channel of perivascular tunnels that help to eliminate proteins and other metabolites from our brain. In a study, it is shown that it mainly works when brain has slow wave activity (mainly seen during sleep). So, yes, you are right that glymphatic system eject majority of metabolic waste during sleep. Regards