Peking Opera performers mainly have two types of facial decorations: masks and facial painting. The frequent on-stage changing of masks or facial makeup (without the audience noticing) is a special technique known as changing faces. 
Changing faces is a difficult technique in operatic performance. It is considered to be a stunt that can only be mastered after extensive training. Face changing is also a special technique used to exaggerate inner feelings of characters, portray their dispositions, set off the atmosphere and improve effects. Facial changes expressing sudden changes in a character's feelings are done in four ways:
Blowing dust: The actor blows black dust hidden in his palm or close to his eyes, nose or beard, so that it blows back into his face.
Manipulating beard: Beard colors can be changed while the beard is being manipulated -- from black to gray and finally to white -- expressing anger or excitement.
Pulling-down masks: The actor can pull down a mask that has previously been hidden on top of his head, leaving his face red, green, blue or black to communicate happiness, hate, anger or sadness respectively.
Mop: The actor mops out the greasepaint hidden in his sideburns or eyebrows, around his eyes and nose, to change his facial appearance.

