Nexus 7 - Wipe Cache

To wipe the cache partition, follow these steps:

1. Turn off the device.
2. Press and hold the Volume Down and Power keys at the same time for about 10 seconds.
3. An image of an Android lying on its back will appear.
4. Press the Volume Down key twice until "Recovery mode" appears on the screen.
5. Press the Power key to restart in "Recovery mode."
6. An image of an Android with a red triangle will appear.
7. Press the Power key and Volume Up keys simultaneously.
8. Use the Volume keys to scroll to "wipe data cache partition" and press the Power key to select.