TAIPEI (Taiwan News) — A plastic NT$50 banknote issued to mark the 50th anniversary of the national currency, the New Taiwan dollar, is extremely difficult to find, the Central Bank said Wednesday (June 15).

The country launched the NT dollar on June 15, 1949, during a period of economic chaos, political repression, and war between the Kuomintang (KMT) and the communists in China.

On its 50th anniversary, in 1999, a polymer NT$50 bill became available to commemorate the event, CNA reported. While a total of 30 million of the banknotes were printed, they were rarely used because people wanted to keep them as souvenirs, and no new versions were issued later.

One side of the bill symbolized Taiwan’s economic development, while the other side featured the Central Bank’s headquarters building on Taipei City’s Roosevelt Road.

The bank said the polymer banknotes were more environmentally friendly, as they could be used 2.5 times longer than the paper version, and could be recycled into flower pots, though they were unable to withstand high temperatures.