MOTO G - wipe the cache partition:
1. With the phone powered off, press the VOL DOWN KEY for 2-3 seconds then POWER key then release.
2. The device will display different BOOT OPTIONS.
3. Use the VOL DOWN Key to SCROLL to Recovery and VOL UP Key to select.
4. The device will display the Motorola logo and then the Android in distress (logo with Exclamation mark).
5a. KITKAT: Press and hold the VOL UP key for 10-15 seconds. While still holding the VOL UP key tap and release the POWER key.
5b. LOLLIPOP: Press and keep holding POWER button for 2-3 seconds, then press and release VOL UP button, then release the POWER button.
Tip: You can try this step, holding the phone in landscape. If you are stuck on step 6, try a force reboot by pressing the Power key and VOL DOWN key, and start the process again.
6. Phone will display menu options, use the VOL DOWN Key to scroll to wipe cache partition and the POWER Key to select this option
8. The device will then perform the partition wipe and reboot.