When you use the Cubby app on Android and save a file for offline viewing, your files are saved to the following location on your SD card:
Note that the /sdcard/ part of the folder path may differ slightly by device.
You can't tell Cubby to save to a different folder.
Offline files are deleted when you log out of Cubby or remove the app from your device. Your files remain in the cloud, but are no longer accessible on your device.