Households do not need to wash cans and jars before putting them in the recycling, according to Richard Kirkman, the UK boss of waste management company Veolia.
Mr Kirkman said food residue left inside containers is removed later using industrial washing equipment. He urged people to ensure their recycling is “relatively clean”, but said there was no need to scrub every item thoroughly.
“If it’s not washed, we wash it in an industrial machine later anyway,” he said. “If it’s washed when we collect it, OK, we use less water — but you’ve used the water at home.”
He said people should not leave half a jar of jam in a container, but added that a small amount of stickiness or gooey residue was acceptable.
Chris Mills, of environmental charity Wrap, also said people should not spend excessive time cleaning tins and bottles before recycling them.
Mr Kirkman said a jam jar that remained slightly sticky, or a plastic yoghurt pot with a small amount left at the bottom, could still go into the recycling.
The main exception is a bottle that is still half full of milk which has gone off, he said.
