A dead pet was discovered among paper and cardboard in a recycling load in Preston.
Preston City Council has issued a reminder to residents in the area of what items can be placed in recycling bins.
In paper recycling loads staff also found used nappies, clothing, a window blind, potatoes and general waste.
Councillor Robert Boswell, cabinet member for environment at the city’s authority, said: “We would always encourage residents to recycle as much as is practically possible, and we thank those that separate the items into the relevant containers.
“Unfortunately, that’s not always the case and recently some loads have been rejected at the reprocessing plant.
“Even if there are only a couple of non-recyclable items included, the whole load could be rejected and sent to landfill at a cost to the taxpayer.
“The rejected load could be the equivalent of all the paper and card collected in Preston on a given day.
“Some of the contamination can happen by mistake, but we suspect that some is deliberate, i.e. bags of residual waste and used nappies in the bottom of recycling bins.
“For the sake of all Preston residents, and for the environment, we would ask people to double check which containers their recyclables are going into in order to minimise contaminating loads in the future.”
For a list of what can be placed in different recycling bins see preston.gov.uk/recycleitems