MALANG, Indonesia - Mahmud hauls bags full of rubbish to the small, dilapidated clinic next to a busy road on Indonesia's main island of Java several times a month.
There he exchanges grubby cardboard boxes, plastic bottles and other garbage for something he would struggle to afford otherwise - medical treatment.
"I know I can sell my garbage here so I keep it," said the 60-year-old, who like many Indonesians goes by one name. "I used to throw everything onto the street but I have started telling myself that actually the garbage is useful."
Mahmud, who suffers from arthritis, is one of many members of the Klinik Bumi Ayu in Malang who regularly bring in rubbish in exchange for check-ups and medicine.
There are five such centres in the city that are part of a scheme dubbed "Garbage Clinical Insurance" by its 24-year-old founder Gamal Albinsaid, offering treatment and advice for free to some of the country's poorest.
As Southeast Asia's biggest economy struggles to spread the riches earned in recent years to the poorest in society, the clinics are a creative attempt to fill the gaps left by a threadbare welfare system.
The government this year began rolling out what is supposed to be a universal healthcare system across the sprawling archipelago of 250 million people.
Once fully implemented by 2019, it is expected to cost around US$15 billion (S$18 billion) a year - but critics say it is underfunded and Indonesia lacks enough well-trained medical staff.
In a country where half the population lives on US$2 a day, spreading the gains from a sustained economic boom has been in sharp focus recently, with contenders running in July presidential elections pledging to better the lot of society's underprivileged.
Beyond healthcare, Albinsaid's initiative has had another notable benefit - it has created an army of cleaners to clear the streets in and around Malang, which like many cities in fast-growing Indonesia struggles to keep litter from piling up.
Albinsaid decided to open a first centre in 2010 after hearing the story of a young daughter of a rubbish collector who died after contracting diarrhoea. Her family could not afford treatment.
That clinic failed to get off the ground, but in 2013, Albinsaid and four others got together the funding to open five centres in Malang, and they have so far been doing well.
His achievements were recognised in January when he was awarded the Unilever Young Sustainability Entrepreneur Prize by Britain's Prince Charles at a ceremony in London, which included US$70,000 in financial support and mentoring.
People who want treatment at the clinics bring in rubbish once a week on Saturdays. They must collect 10,000 rupiah (S$1.20 cents) worth of garbage every month to be a member of the scheme, and this qualifies them for two visits a month.