I usually use Ubuntu tweak to do cleanup jobs on my PC. This includes apt and program cached data and old kernels. This goes alright for most programs except Mozilla based application - Firefox and Thunderbird.
Ubuntu tweak doesn't seem to know where their cache folders are and always returns 'zero packages can be cleaned' even when the cache folder is full. Check screenshot below:
I am looking for a way to clean up ALL my cache data and unneeded packages at one point.
If someone knows how to change the ubuntu tweak cache folders for Firefox and Thunderbird, that would be perfect.
I tried bleachbit last but it crashed my PC to a point I had to re-install Ubuntu.
I am using Ubuntu tweak 0.8.6.
Same issue with the screenshot of this question: Why isn't Ubuntu Tweak's Janitor working?
For the python programmers out there, this answer shows the commands that Ubuntu tweak janitor runs to clean up the system. Maybe something in there will shed more light to this issue.