Every year Hungary recycles approximately $1 billion worth of worn out forints, and converts the used currency into bricks. These bricks are sent to several charities, so they can burn them as heating fuel. The program allows the organization to cover up to a third of their annual heating costs.
Banknotes undergo a quality check at the logistics centre of the National Bank of Hungary in Budapest. Once they are taken out of circulation, the bank notes are recycled for fuel, and a few charities each year get 20-30 tonnes of paper bricks each. Banknotes are shredded and compressed into heating fuel in the shape of bricks.
As per Reuters, Hungary is the only country to recycle its worn cash for fuel each year.