Military Payment Certificate (MPC) Series 641 10c Cents Grades xf+. Military payment certificates for the series 641 were the first notes used in Vietnam; that is also the only country in which these were used. They were originally issued on August 31st, 1965. They were redeemed on October 21st, 1968. Military payment certificates, or MPC, were a form of currency used to pay U.S. military personnel in certain foreign countries. They were used in one area or another from a few months after the end of World War II until a few months after the end of U.S. participation in the Vietnam War – from 1946 until 1973. MPC utilized layers of line lithography to create colorful banknotes that could be produced cheaply. Fifteen series of MPCs were created. However, only 13 series were issued. The remaining two were largely destroyed, although some examples remain. Among the 13 released series a total of 94 notes are recognized.