Istanbul on Wednesday rolled out an alternative currency for commuters who need to top up their subway cards but are short of cash: recyclables.

The city is installing “reverse vending machines” at metro stations that allow passengers to add credit to their subway cards simply by inserting a plastic bottle or aluminum can into the machine.

Once a value has been assigned to the recyclables, the machine will crush, shred and sort the material.

The initiative aims to encourage recycling in the city of more than 15 million people, where recycling practices are scant or indifferent. But the alternative way of paying to travel is sure to be welcomed by commuters, as Turkey’s currency has been hammered lately, falling to record lows against the dollar because of soaring inflation, economic mismanagement by the Turkish government and tensions with the United States.