Recycling bins being contaminated with general waste could cost Fife Council more than £500,000 per year in lost income and increased processing charges.
The problem is affecting all the materials that are being collected for recycling from kerbsides.
Recycling companies are finding food waste, nappies and even dog excrement in paper recycled by Fifers, while food and garden waste is being contaminated with glass, plastics and rubble.
Environment and transport spokesman PatCallaghan, said: “We have a tremendous recycling record. Fife recycles more waste than any other council in the Scotland.
“We also have a fantastic record for providing high-quality, contamination-free materials from the kerbside recycling bins.
“This has been down to the way in which the vast majority of Fifers have embraced the recycling services provided by the council.
“In recent years this performance has saved millions of pounds in landfill tax and has also provided a multi-million-pound income stream.
“Without this financial benefit, vital council services would be at risk.
“Unfortunately, over the last few months, we have seen more recycling bins being contaminated, even in areas where we’ve had very few problems in the past.
“The immediate impact is an increase in costs because the material has to be processed to remove contamination.
“It also means reduced income since the value of contaminated material is a lot less than the high-quality recyclates that we are used to supplying.
“Worse still, if the current contamination levels remain, there’s a risk that we might not be able to find buyers for some materials.”
Mr Callaghan added: “Even small amounts of the wrong waste can lead to problems at the processors.
“I believe people are trying very hard to recycle as much as possible but if you’re unsure about what can be recycled, or if you’re finding the service difficult, please take a look at the advice at www.fifedirect.org.uk/wasteaware or call us on 03451 550022.”