Scrap Metal is a new type of currency that appears in Epic Mickey 2: The Power of Two. It replaces the normal E-Tickets when the situation requires building or rebuilding things. It can be acquired through demolition.
Scrap Metal is mostly needed in the two parts of Mean Street (in Mean Street South by the Blue Gremlin and in Mean Street North by Gremlin Jamface). It can be traded at the The Wasteland Pin Trading Company for default pins.
The only time it is used during the story is by Petetronic who, depending on if Mickey decides to help him with the Blotworx, will give 80%/all of it back to Mickey. Petetronic will take all the Scrap Metal the player has at the time of visit.