Magnets are being used by a Devon farmer to protect his cows.
Disused Chinese lanterns, nails and wire fencing are responsible for causing the deaths of a number of cattle.
David Partridge, who farms at Tiverton, has now inserted the 8cm (3in) magnet into 700 of his animals' stomachs.
Any metal swallowed accidentally by his herd will stick to the device, helping to prevent the heart and lungs from being punctured.
"Everybody has odd bits of metal lying around," Mr Partridge told BBC News.
"Barbed-wire staples come out of stakes and when a cow's grazing, it's not fussy what it eats."
The growing popularity of Chinese sky lanterns set off at weddings, parties and barbecues has resulted in more problems for farmers because of the wire used on the lanterns' frames.
In a written response to South West MEP Julie Girling about the dangers from the lanterns, the EU Health Commissioner John Dalli said magnets were a useful preventative measure as any metal objects or foreign bodies left on farmland could harm or kill livestock.
Cattle vet Andrew Biggs said the stomach magnets were safe and would attract any metal that had been eaten.
"They do swallow it quite well and the weight generally keeps it in the stomach," he said.
"Cows are ruminants and they do regurgitate their food and chew the cud, so occasionally some will be spat out."
The National Farmers' Union would prefer to see a ban on Chinese lanterns, claiming they not only pose a danger to livestock, but could damage crops, trees and farm buildings if they land while still alight.