In 1975, the “Ang Bagong Lipunan” series was introduced with different designs, specifications and denominational mix from the Pilipino series. Aluminum replaced bronze and cupro-nickel replaced nickel-brass coins. The 5-piso coin was introduced while the 50-sentimo coin was deleted in the series. The entire series of ABL coins was considered demonetized after January 2, 1998.
images and site source: bsp.gov.ph