Used Mobiles Contain personal Data

Consumers are passing private personal data to strangers when they discard or sell mobile phones,with photos,videos,credit card numbers and pin numbers.Any data left on the phone is effectively open to  the public domain.Mobiles store data in different places, depending on hardware model, software, and user preference,
Deleting sms is unlikely to remove the data from the mobiles.
FACTORY RESET IS THE SAFEST AND MOST RELIABLE WAY
TO ERASE PERSONAL DATA BEFORE DISPOSING OF (OR)
SELLING A HANDSET.