You can uninstall or removes an installed pidgin-plugin-pack package itself from Ubuntu 14.04 LTS (Trusty Tahr) through the terminal,
$ sudo apt-get remove pidgin-plugin-pack
If you would like to remove pidgin-plugin-pack and it's dependent packages which are no longer needed from Ubuntu,
$ sudo apt-get remove --auto-remove pidgin-plugin-pack
If you use with purge options to pidgin-plugin-pack package all the configuration and dependent packages will be removed.
$ sudo apt-get purge pidgin-plugin-pack
If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.
$ sudo apt-get purge --auto-remove pidgin-plugin-pack