At the jail's handmade paper unit, the raw material has now changed from waste paper to shredded banned notes. T Rajan (name changed), who is serving a life sentence, breaks balls made of shredded notes and drops them into a pulp pond. A few others stir the pond as a motor grinds the paper into a pulp.
The pulp is then poured into moulds, compressed to form cardboards. Another group of men cut them to size and turn them into office file-holders by sticking flyers and neatly wrapping them with colour papers. These stationery products are then supplied to government offices across Tamil Nadu.
The Reserve Bank of India has given them seven tonnes of the banned notes, enough to make 14,000 file-holders. The prisoners make some 200 file-holders a day; 50 prisoners at this unit earn up to Rs 200 a day.
P Moorthy (name changed), who is also serving a life sentence, gets emotional as he handles shredded notes of all denominations. "It's for this money only we struggled earlier when we were free outside. Now after the government announced them illegal, we are recycling these into a new product. We are happy," he says.
They will be released on the birth anniversary of late Chief Minister J Jayalalithaa on February 24.
"My dream is I want to live with my wife and child happily and start life afresh," Darwin says.
M Virumandi (name changed), another man serving life sentence, says he is no that lucky as he has done only nine years so far. "This experience would help me to do something on my own after my release later. I'm happy for my brothers in jail who would be set free," he says.
The sprawling 200-acre Puzhal jail is one of the largest prison campuses in India.
"We have several such ventures to empower inmates, including a modern bakery, garment and shoe polish-making unit. However, making file-holders using banned currency notes has taken recycling to a new level," a senior police officer told NDTV.