Increasing amounts of household waste in Plymouth are being rejected for recycling according to figures from the Department for Environment, Food and Rural Affairs (Defra).
Since 2006 the amount of waste rejected has risen from 9.8% to 21.5% in 2009.
In 2006/07 1,450 tonnes of the total 14,856 tonnes were rejected, but in 2008/09 3,519 tonnes of the total 16,332 tonnes were rejected.
Plymouth City Council said it was hoping to educate people better.
The council collects waste for recycling in a separate bin to non-recyclable waste once every two weeks.
It then sorts out the recyclable material at its waste depots.
Recyclable material includes paper, cardboard, plastics, food and drinks cans, aerosols and aluminium foil.
Waste it does not recycle includes cellophane, glass which can be recycled at recycling banks around the city, Tetra packs, crisp packets, sweet wrappers, polythene and polystyrene.
Councillor Michael Leaves, cabinet member for waste, said: "The message has not got across.
"Some people do not like recycling and some people do not recycle."
He said all the details about what could be recycled were on the council's website.
"We are putting more effort into educating people and we are recycling all the material we can," he added.
The Defra figures showed that in 2009 Teignbridge District Council was unable to process 463 tonnes of waste for recycling, much of which was as a result of breakdowns in its composting facilities.
In other years the figure for Teignbridge District Council has been nearer 23 tonnes.
Exeter City, Torbay, South Hams District, Torridge District, North Cornwall District, North Devon District, West Devon District, East Devon District, Mid Devon District said no materials were rejected.