A new report has revealed that 3,000 tons of recyclable waste could not be processed because residents had put the wrong things into the bags - costing the council an extra £57,000.

Rogue items contaminated the other waste, meaning it all had to be sorted differently or incinerated to generate energy.

The top offending items were sanitary products (such as nappies), food, small electrical items, batteries and textiles.

Another problem encountered by council contractor Medway Norse concerned items like glass cooking dishes or metal saucepans.

Although they can be recycled, they are not included in the specific residential collections, which is limited to glass bottles and jars, metal food and drink cans, clean metal foil, and plastic bottles, pots, tubs and trays.

The additional work for waste collectors cost the council £57,000 between October last year and this September.

Councillors asked how the 3,000 tons of otherwise recyclable rubbish could be reduced.

The report said the 20% figure was unchanged from previous years and this level of contamination was a continuing challenge despite efforts to raise public awareness.

At the regeneration, culture, and environment (RCE) overview and scrutiny committee, councillors asked officers and representatives from Medway Norse about what efforts were being made to reduce the amount of rubbish that was unable to be recycled.

The report said “robust communications messages and interventions” were being made to try and get residents to put the right items in the right bags, and Cllr Matt Fearn (Con) asked what these were and how they might be improved to get better results.

He said: “I haven’t knowingly seen what those robust communication messages are. Is it something we can use in our newsletters and feedback to residents?

“What are we actually doing? Because that level is the same. For me, I don’t think that is quite robust enough.”

Ian Gilmore, head of regulatory and environmental services for Medway Council, said: “We have an environmental engagement team who do more events than I can discuss and try to educate people on maximising our waste strategy.

“We can engage and we can talk and we can persuade and we can cajole, but we need residents to go on that journey with us. It’s immensely hard and it’s frustrating for us and as much as you can champion that we would really welcome that.”

Andrew Mann, managing director of Medway Norse, added that a lot of communication about contamination of recycling was already out there in Medway Matters and other places, but that they were exploring further avenues, including information printed on the clear recycling bags.