Another beautiful scene by Milt Kahl.
This is sequence 2, scene 118. "So, I am going to be your tutor." Merlin proclaims to Wart.
The wizard opens a book, before proceeding to clean his glasses. The main business here is the subtle action of Merlin's hand using part of his moustache to wipe the glasses clean. It reads beautifully, because Milt played down everything else in the scene. It teaches us again that if you want to communicate subtle movement, it needs to be isolated. Nothing else should move.
The idea to use the moustage to clean Merlin's glasses is pure Disney. And Milt staged this exquisitely. Study Merlin's hand, as it wipes the glasses. Awesome!!