You might have any one or more of several good reasons for wiping your smartphone. You might be selling it, or the phone might be having problems and you want to start again. At worst, it might have been lost or stolen.
Alternatively, you might just want to delete your browsing history, or stop certain apps from reporting your location. Whatever the reason, it actually isn’t at all difficult or complicated to do.
Generally speaking, most apps on your smartphone will keep some data in storage. Sometimes it won’t be a lot, other times it will be a ton of stuff. By far the biggest keeper of data will usually be your browser, and then social media apps like Twitter or Facebook. Of course, we don’t need to tell you how personal and potentially damaging some of that data might be.
So how do you delete data by app? Well, you have two ways. The easiest way is to go to all apps and long-click the app you want to check. In the popup, select the App Info icon (an ‘i’ in a circle) to see a general bank of information about the app. Tap the Storage option and you can see how much space the app itself takes up, how much data it has used and how much space the cache of the app is using. You can clear the cache or even all data for the app from this screen. If the app you’re looking at is a browser, the cache will likely have all the sites you’ve recently visited. It stores them so that, if you go to the site again, it will reload the page(s) from the cache to speed things up.
On the downside, it might also store information you’ve entered into forms or other online stuff. This might depend on the settings you have for the browser app.
To simply clear information temporarily stored for use later, hit the “Clear Cache” button. To clear all the app data stored, effectively resetting the app to a “just-installed” state, hit “Clear Data”. Be aware that this will delete things like saved logins or other information.
The iOS method is similar to that for Android, but a little less convenient if you want to reset the app.
Go to Settings > General > iPhone Storage. The apps on your iPhone will appear in order of the most space used to the least. Tap the one you want to clear, and you will have the option to delete the app. You can’t just clear the data in iOS, you must delete and reinstall the app. To be fair, this method can be useful on Android if an app is still misbehaving after clearing the data. However, it does seem like an excessive first step on an iPhone.
If you want to just clear the cache of Safari, this must also be done within the main settings. Instead of going into Storage, there is an option for Safari. Tap that and you can clear the cache there.
If you have lost your Android device, both locking and wiping it can be done within your Google account. If you chose not to set up a Google account when you set the phone up, you will not have this option. Otherwise, log into your account in any browser (this is not Gmail, by the way, this is your main Google account) and click your avatar in the top right. Click on “My Account”, and you will see an option on the next screen to “Find My Phone”.
Click that, and you will then have several options including both locking or resetting the phone altogether.
You also have the option in the device settings. In Settings > System you should see “Reset Options” or something similar. Unfortunately, Google have the habit of changing the terminology they use from version to version of Android, but it should be fairly obvious. In there, you will see an option to return your phone to the factory setup. Although, technically, you could reverse this if you have a backup of your phone, not everything is stored in Google Drive, so consider it full and final. As an example, texts aren’t backed up, and nor is much of the app data you have.
If you’ve lost your iPhone, log into icloud.com to use your Apple account to locate it. If the phone is unrecoverable, you will have the option on iCloud to erase it completely.
To do a factory reset, if you sell the phone for example, then this can be done on the iPhone itself. Go to Settings > General > Reset > Erase All Content And Settings. Select the device, and click Erase. Once done, click “Remove From Account”. Note, you must be logged out of iCloud and iTunes, or you cannot erase your iPhone.
If you have simply finished with your smartphone, and don’t want anybody else to have it, you can just do the factory reset described above and leave it in a drawer. But, if you really want to kill it so it can never be used, it isn’t so straightforward. Just about the only way is to smash it to pieces, or put a drill through it. Any other method might not physically destroy it, never to be recovered. The problem with this is that batteries in smartphones are extremely hazardous both to your health and to the environment if not disposed of properly.
Use Google to find somewhere that will recycle the battery. You can try and hand it back to an Apple Store if you have an iPhone. Whether they accept it seems to vary from store to store, but it’s worth a try. Some electronics stores will also accept batteries for recycling. Please, whatever you do, don’t just throw it in the general trash. The rest of the phone, you can pretty much do what you want with.
Do think about recycling the phone, though. Third world countries are grateful for old mobile devices, so do a good deed.