Eu também estava no mesmo barco quando tinha 14.04 Agora estou no Velvet!
Aqui está o script de solução que eu trabalhei para mim:
#!/bin/bash
echo
echo Install BleachBit
echo
apt-get install bleachbit -y
echo
echo Clean
echo
apt-get autoclean
apt-get clean
echo
echo Update & Upgrade
echo
apt-get update
apt-get upgrade
apt-get dist-upgrade
echo
echo
echo BleachBit Cleaning
echo
bleachbit -c adobe_reader.*
bleachbit -c apt.*
bleachbit -c chromium.*
bleachbit -c deepscan.*
bleachbit -c epiphany.*
bleachbit -c evolution.*
bleachbit -c filezilla.*
bleachbit -c firefox.*
bleachbit -c google_chrome.*
bleachbit -c kde.*
bleachbit -c java.*
bleachbit -c system.cache
bleachbit -c system.clipboard
bleachbit -c system.custom
bleachbit -c system.desktop_entry
bleachbit -c system.localizations
bleachbit -c system.memory
bleachbit -c system.recent_documents
bleachbit -c system.rotated_logs
bleachbit -c system.tmp
bleachbit -c system.trash
bleachbit -c opera.*
bleachbit -c thumbnails.*
bleachbit -c transmission.*
bleachbit -c x11.*
bleachbit -c vlc.*
bleachbit -c wine.*
echo
echo Clean Up
echo
apt-get clean
apt-get autoclean
echo
echo BleachBit ReBleach System
echo
bleachbit -c system.cache
bleachbit -c system.clipboard
bleachbit -c system.custom
bleachbit -c system.desktop_entry
bleachbit -c system.localizations
bleachbit -c system.memory
bleachbit -c system.recent_documents
bleachbit -c system.rotated_logs
bleachbit -c system.tmp
bleachbit -c system.trash
echo
echo Processes Complete
echo