Properly Dispose your iPhone
Prior to dispose of a working iPhone erase all content on your device to protect personal data. Please do not throw your iPhone in the trash. Working units have both cash and functional value allowing you to sell them, donate them or send them into Apple's reuse program to receive an Apple gift card for market value.
Fully charge your iPhone or connect it to a power source prior to erasing.
Tap "Settings" on the iPhone's home screen, followed by "General" and then "Reset."
Tap "Erase All Content and Settings" and confirm to erase the iPhone. This could take several minutes to complete. Now your iPhone when you are ready to dispose of it.
If you don't want to use Apple's recycling program, you could donate the iPhone to a charity, give it to a friend or sell it to a third-party.