How clear/clean unneeded files or cache for my customized distro

Can you help me to find out how do I clear the Cache files or unnecessary or lib that can be updated on new Ubuntu install.

I used "Ubuntu 12.10"

This my top size file/folder list:

4380MiB /usr
2784MiB /usr/share
1641MiB /usr/share/icons
1541MiB /usr/share/icons/codex
1424MiB /usr/share/icons/codex/.icon-theme.cache
1263MiB /usr/lib
513MiB  /usr/lib/i386-linux-gnu
213MiB  /usr/share/fonts
208MiB  /usr/bin
199MiB  /usr/share/fonts/truetype
179MiB  /usr/lib/libreoffice
138MiB  /usr/lib/libreoffice/program
131MiB  /usr/share/locale
106MiB  /usr/lib/i386-linux-gnu/wine
100MiB  /usr/src


399MiB  /var
196MiB  /var/lib
188MiB  /var/cache
88MiB   /var/cache/apt-xapian-index/index.2
88MiB   /var/cache/apt-xapian-index
87MiB   /var/lib/apt
86MiB   /var/lib/apt/lists
80MiB   /var/lib/dpkg
72MiB   /var/lib/dpkg/info
51MiB   /var/cache/apt

Bleachbit (source) helped me for clear cache and unneeded files:

sudo apt install bleachbit