Taken from the world of cinema and CGI (computer-generated imagery), this refers to the controlled ageing, weathering and worrying done to the set, props and costumes of a movie to give the viewer the impression of an old or used or weathered mise-en-scene.
I'm directing a picture about 18th century France, and my artistic designer currently has hands simulating an authentic look of the period by using charcoal and mud to dirtify all my sets.