Before you recycle or resell that mobile phone, are you sure it is clear of all your personally identifiable information? Manually deleting data leaves a lot of information latent in the device which can later be found by the next owner using data recovery tools.
A recent study conducted in the United Kingdom found that more than fifty percent of secondhand mobile phones contained personal or financial data including social network login credentials, credit and debit card PINs, bank account details and company information. Before selling or donating their mobile phones 81% percent of respondents claimed they deleted all personally identifiable and sensitive information, but just manually deleting data leaves a lot of traces on the mobile device.
Restoring to the factory default reset is recommended to fully clear your phone of sensitive information and should be done before selling, donating or disposing of a cell or smartphone. In fact, smartphones have more capabilities to store information and that information is easier to recover than with traditional mobile phones according to the study.
An integral part of most mobile devices is the SIM (Subscriber Identity Module) card, which can be sold or donated with a mobile phone or by itself. As part of the same study white hat hacker Jason Hart bought 50 SIM cards on eBay, 27 of which still contained personal information of the previous owner. Whereas restoring factory defaults is sufficient to rid a mobile device of PII, the only remedy for SIM cards is to destroy them. If you are upgrading mobile devices transferring the SIM card is a convenient way to keep all your contacts, but if you don't need it be sure to destroy it, and don’t sell it or give it away.