If you get strange locale errors when running perl and GTK apps, run these commands and be sure to generate all en_US locales:

$ apt-get install localeconf
$ dpkg-reconfigure locales

Use this command to purge old configs and files from your system that are in uninstalled packages:

$ dpkg --get-selections | awk '/deinstall/ {print $1}' | xargs dpkg --purge