The foul remnants of a drool-ridden sleep, or the substance located at the medial corner of the eye. Morning Crust can be found dotted around your lips, chin or cheeks after waking up from a good to excellent sleep or nap. Morning crust can also be discovered in the eyes, a small white build up of salt and water from your tear ducts can develop, thus leaving you with "Crusty eyes."
"Yo, Bill...you've got some mad Morning Crust in and around your mouth"
"Oh thanks John, you saved me some embarrassment, I hate Morning Crust"