Under Debian for most Linux distributions you can free up some disk space, simply by deleting the configuration files resulting unistallation of packages.
The commands to be used are:
dpkg –purge $dpkg –get-selections | grep deinstall$ | cut -f 1
dpkg –purge $dpkg –get-selections | awk ‘$2 ~ /de/ { print $1 } ‘
aptitude clean
dpkg –purge $deborphan