Clear Cache Data: 
FT8CN keeps a list of followed callsign and decoded messages in the cache file. You can permanently delete those using empty cache option. 

Note that clearing cache won't delete any QSO log.

List of followed callsign:
This list contains all your followed callsigns. When a followed callsign shows up, it will be added to the calling message for quick-call or auto-call.   

Note that clearing the list of tracked callsign will remove all saved favorite callsigns.

Clean "cached QSO decoding":
FT8CN can save all decoded messages. You review them from Web UI. (Not on main UI yet)