Check out how to easily wipe cache partition in POLYTRON T7800 Cosmica. This operation won't affect your personal files it will only remove temporary cache files. As a result you can refresh Android 4.2 Jelly Bean system and optimize .
Let's start process holding the Power key in order to turn on your phone.
If your device is disable, hold the Volume Up and the Power rocker simultaneously
When the POLYTRON logo will show on the POLYTRON T7800 Cosmica screen, release held buttons.
In the Recovery mode find Wipe Cache Partition using Volume Keys and confirm it by the Power key.
Afterward, you have to select Reboot system now to enter system.