Recycling bins around Dunedin will be checked from today to make sure residents are doing the right thing and recycling correctly.
The inspections are intended to reduce contamination rates and keep the staff who collect and sort the recycling safe.
Dunedin City Council waste and environmental solutions group manager Chris Henderson said a similar inspection programme introduced last year led to the contamination rate dropping from 11% to 7.1%.
There was also a 27% improvement in recycling content for bins that were checked at least three times, Mr Henderson said.
Bins around the city will be checked again for 12 weeks from today.
The two most common recycling mistakes were soft plastics and milk and juice cartons, none of which could be recycled at the Green Island recycling plant.
General and hazardous waste such as nappies, medical waste, dog faeces and cigarette butts were also found in the checks last year and were still ongoing issues, he said.
"It was great to see improvements, but we want to remind people about what is OK to recycle and will again provide feedback by using coloured tags."
The bin checks were an opportunity for the council to give guidance on what was correct when it came to recycling, he said.
In 2016-17, Dunedin residents put more than 8500 tonnes of material into recycling bins and about 11%, or 960 tonnes, was contaminated.