Nottinghamshire Police say that criminals have been using electronic gaming machines to launder illegitimate dye-stained notes.
A number of dye-stained notes have been found across Nottingham in the machines and handed-in to officers. The force is now warning businesses to be on their guard against it happening in the future.
The penalty for forgeries range from nine months to ten years. Despite this the police say that it is a common way for the notes to come into circulation because of the difficulty of tracing the culprit.
The police and the Nottinghamshire Police and Crime Commissioner, Paddy Tipping, stress the importance of protecting your own business from criminals by making use of safety checks such as highlighter pens, UV lights and CCTV.
Paddy Tipping says that anyone caught using fake money will be handed over to the police.
He says advances in technology give criminals the opportunity to commit high level fraud, but at the same time it is more difficult for police to catch the culprit.