The only way to stop fraudsters stealing information from old computer hard drives is by destroying them completely, a study has found.
Computing magazine Which? recovered 22,000 "deleted" files from eight computers purchased on eBay.
Criminals source hardware from such internet auction sites or even in rubbish tips, to find valuable details.
Freely available software can be used to recover files that users think they have permanently deleted.
The only solution, according to Which?, is complete destruction - and it recommends using a hammer.
A number of recent cases have shown the dangers in disposing of second-hand equipment, from which details as well as other personal files can be retrieved.