Recyclable plastic waste.
题意:泗水的当地人现在能用什么代替钱来支付公交车费呢?
根据第一段最后一句:
But one Indonesian city has decided to accept recyclable plastic waste instead of money for city buses. 但是印度尼西亚的一个城市已经决定接受可回收的塑料垃圾代替钱来支付城市公交车车费。
以及第二段第二句:
Now, locals can pay for their bus rides by putting plastic cups or bottles directly on the bus. 现在,当地人可以把塑料杯或塑料瓶直接放在公交车上支付车费。
可知泗水的当地人现在能用可回收的塑料垃圾,比如塑料杯或塑料瓶,来支付公交车费,故答案为:Recyclable plastic waste./(Plastic cups or bottles.)