看看这个link： http://www.mta.info/metrocard/problems.htm
Pay-Per-Ride (Regular) MetroCard Go to a station booth and ask the station
agent to transfer your money to a new card. If the card is too damaged for
the agent to read, it will have to be mailed to NYC Transit.
Unlimited Ride MetroCard must be mailed to NYC Transit for replacement. To
receive a full credit for time remaining on your card, the envelope must be
postmarked no later than one day after the problem occurs. Sundays and
Federal holidays are not counted.
