The next time you want to travel from Rome’s Termini train station to seek forgiveness at the Vatican, you may want to pick up a few plastic bottles along the way. While plogging is always cool, those collected plastic bottles serve a different purpose. Rome is testing a scheme where people can swap plastic bottles for subway rides.

The Italian capital has launched a 12-month trial of the program called “Ricicli + Viaggi,” or Recycle + Travel, at three subway stations. The program allows commuters to deposit plastic bottles in return for five euro cents each, according to The Local, which can be used toward the cost of a ride on the metro. Those cents can be accrued on the metro app until they hit the price of a metro ticket, which is currently €1.50. For the math-challenged, that means a ride costs 30 bottles, which means 30 fewer plastic bottles eternally littering the streets of the Eternal City. After the year-long trial is over, Rome will review the results to see if the scheme should be expanded beyond its initial three stations.

While this recycling program is clever, as Environment Minister Sergio Costa pointed out in a Facebook post, “the ideal thing would be to consume less single-use plastic and opt for reusable bottles.” But if you do buy a plastic water bottle or find one littering the street, you can trade it in toward a ride on the subway.

Rome’s mayor, Virginia Raggi, who back in March promised a ban on single-use plastics, said the project is the first of its kind in a “large European capital,” although a similar system is in place in Istanbul’s subway system, so perhaps that was some subtle “large European capital” shade. Istanbul has had “reverse vending machines” at its metro stations since late 2018. Its version allows passengers to add credit to their subway cards by recycling a plastic bottle or an aluminum can into the machine. And Surabaya, Indonesia lets passengers swap just five plastic bottles for bus tickets.

If you’re lucky enough to be headed to Rome soon, bring me, and we can test the machines that are currently at the Cipro station on Line A, Piramide on Line B, and San Giovanni on Line C.