As of September 2014, torn dollar bills can be exchanged at any bank as long as more than one-half of the bill is still intact. If this is not the case, then the bill must be examined by the Bureau of Engraving and Printing.
It is necessary to note a bill's approximate worth when sending it to the Bureau of Engraving and Printing. The bureau also requires a letter explaining how it was damaged. The damaged bill should be left in its original container, such as a purse or a box, to prevent further damage to the bill and help the investigator make a decision.
The U.S. Mint handles matters relating to damaged coins.