Steve Tsoukalas, who has been working at the Opera House for 49 years, is responsible for the green cleaning revolution at the site. Credit:Peter Rae Those "two ladies" are his wife of 49 years, Marina, and the Opera House, designed by Danish architect Jørn Utzon to last 250 years at least. Mr Tsoukalas started as a builder and scaffolder when the drama theatre was still a mess of rocks and water. Old photos show him climbing to the top of the sails without a safety harness. The young migrant ran a crew who carried 55 kilometres of scaffolding pipes across the site. When construction was over, he worked on maintaining the site. After decades of watching the wear and tear of the building from visitors, he wanted to restore the building without using harsh chemicals.

Opera House cleaner Steve Tsoukalas on his wedding day with wife Marina in 1968. Credit:Tsoukalas family "For 49 years you come [in here] at 5am in the morning; you are in love with it and every day you go around looking at what damage there is, and you have to report it," he said. "The reason I try all these years to find a solution to not using chemicals [is] because I love the building and I don't want it to be sick. If it is sick, I am going to be sick. " Steve Tsoukalas with architect Jan Utzon, son of Jorn Utzon. Credit:Tsoukalas family Remembering cleaning techniquesused by his grandmother on the Aegean island of Kalymnos where he grew up, Mr Tsoukalas asked his wife to go to Coles and buy him a box of bicarbonate of soda.

He wondered if it would restore the building's concrete arches, which had been damaged by years of smoking inside the House, human oil and other stains. Steve Tsoukalas working on the Opera House in the 1960s. Credit:Tsoukalas family The thing is I fell in love with two ladies ... the Opera House and my wife. Steve Tsoukalas To test his theory, he sprayed a solution of bicarb dissolved in water on concrete in the Utzon room. A few minutes later he rubbed it off with rags.

It removed decades of grime. "It was a success," he said. A photo of the clean concrete – looking as good as it did decades ago – was sent to the late Mr Utzon, who was then living in Majorca. "The answer was: 'Tell Steve to do all the Opera House like that'. He was so happy." This solution is now used to clean all the concrete in the House. Mr Tsoukalas also introduced other natural cleaning techniques, which have formed the basis of the House's eco-friendly cleaning guidelines.

The untreated southern blue gum timber flooring in the Utzon room, for instance, is cleaned with a mix of one cup of Lux washing soap flakes and one cup of Kaolin fine grade clay dissolved in a bucket of water. Chemical cleaning agents may permanently mark and darken the timber. Bronze railings are burnished with a solution of South Australian olive oil with a small amount of methylated spirits, the same solution that Mr Tsoukalas' wife uses to rub her husband's back when his sciatica plays up. For many years, cleaners applied bees wax to the bronze, but it become as hard as steel, Mr Tsoukalas said. The olive oil softens and helps remove the wax. "My grandmother used to do something similar" said Mr Tsoukalas, remembering the woman who brought up his large family after his mother died when he was three. To disinfect the Opera House, water infused with ozone, which creates a safe, milder cleaner, is used. The Opera House's environmental sustainability manager Emma Bombonato said the new green cleaning guidelines and products protected not only the building, but also the environment and people visiting and working there.

Staff have found the green methods achieve the same results as chemical cleaning agents previously used, and they comply with Good Environmental Choice Australia (GECA) recommendations for products. "In terms of a conservation plan and world heritage, we want to ensure the building lasts," Ms Bombonato said. Now fighting retirement, or the "sunrise" of his working life, Mr Tsoukalas has cut back work to two days a week, a concession by his wife who realises that working at Bennelong Point keeps her husband healthy and happy. Even now, Mr Tsoukalas bursts with pride and gratitude. Unusual for a news story, he repeatedly asked this reporter to include his thanks to the House's chief executive Louise Herron and others for letting him take care of the building.

How could we refuse? "Thank you," he said many times.