Put a floating bin in Sydney's Darling Harbour for 14 hours and what do you get?
Cups, bags, panels of polystyrene and tiny pieces of plastic, for a start.
"If you look closely at the natural debris here, you can see quite a lot of cigarette butts," Pete Ceglinski told reporters.
The co-founder of the Seabin Project, having taken his invention around the world, demonstrated the device for the first time in Australia on Friday.
The floating bin was kept in the water overnight to coincide with World Oceans Day.
Mr Ceglinski invented and developed it three years ago with fellow Aussie Andrew Turton.
There are now 52 in 14 countries collecting roughly 10 to 15 tonnes of waste from the world's oceans.
The pair launched their design following a successful crowdfunding campaign and a social media marketing strategy.
"We wanted to see how community and social media and word of mouth could work," Mr Ceglinkski said.
"The video went viral and the local community have been pushing government and marinas to get onto it ever since."
The bins, which double as scientific water monitoring stations, collect up to 1.5kg of waste every day including microplastics as small as 1mm in length, and oil.
More than 50 countries are putting in orders for another 7600-plus bins to put in 450 marinas.
Mr Ceglinski has been blown away by the demand, including a 10-year-old Irish girl crowdfunding to raise money to install one in her community.
"I think the community are just super sick of seeing the debris in the water and they want solutions, and they also want to help," he said.
Australian Associated Press