1. Encrypt your gadget's data
Are you familiar with encryption? It's not just for protecting secret government documents and confidential business files. You can actually encrypt all of the data in your gadget, and it's a necessary step in wiping it securely.
To do this, you'll need your trusty gadget, its charger and about an hour. Plug your gadget in, go to your "Settings" page. Then Security >> Screen Lock or Encrypt Device, depending on your device.
You'll be prompted to create a unique password or lock PIN, and that's completely normal. This is to allow you to perform an encryption. Write this password down, as you may need it later. Just be aware that once you encrypt your Android gadget, there's no going back.
You'll see a progress bar appear after you agree to the encryption terms. This process can take about an hour, and you don't want to interrupt it. Doing so can permanently damage your gadget.
You'll be alerted once the process is complete, and then it's time to move on to the next phase.
2. Remove memory card
The next step is physically removing your memory card if you have one. Most people forget these are even in their gadgets after they put it in when they first get their phones.
Just in case you weren't aware, many Android gadgets let you plug in a memory card to expand the storage space. Memory cards range in storage size and keep videos, photos, music and documents on your smartphone without slowing it down.
The memory card is generally located under the back plastic plating and it's a small, removable square like the one seen above.
You can take this external memory card and use it in your next smartphone or you can get rid of it forever. Just make sure to break it in half if you do decide to get rid of it, that way it can never be accessed again.
3. Factory reset
When you finish the steps listed above, you can initiate a factory reset. To do this, go to Settings >> Backup & reset >> Factory data reset. This will erase all of the data and take your gadget back to the settings that were on it when initially purchased.
You'll need the charger for this part, too. Factory resets can eat up a battery in a flash and you want to make sure that the reset executed completely to avoid damaging the Android.
Only do this when you're totally ready to get rid of the phone. You can't reverse a factory reset; all of your contacts, photos, videos, calls and texts will be erased forever.
Once the factory reset is complete, you can feel secure selling or trading in your Android gadget.