EBAY is clamping down on unscrupulous traders illegally selling ancient gold and silver coins.
The auction website has linked up with police and the British Museum to create a trading guide.
People finding treasure trove have to report it, but some sell it instead.
Now Ebay vendors must make clear items have been reported. Suspect listings will be passed to police. Det Sgt Vernon Rapley, of the Met, said: "We hope this has a real impact on illicit sales."
Hopefully eBay will go beyond just coins and will start looking at some of the antiquities sellers in general.