You can uninstall or removes an installed gedit-valatoys-plugin package itself from Debian 7 (Wheezy) through the terminal,
$ sudo apt-get remove gedit-valatoys-plugin
If you would like to remove gedit-valatoys-plugin and it's dependent packages which are no longer needed from Ubuntu,
$ sudo apt-get remove --auto-remove gedit-valatoys-plugin
If you use with purge options to gedit-valatoys-plugin package all the configuration and dependent packages will be removed.
$ sudo apt-get purge gedit-valatoys-plugin
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 gedit-valatoys-plugin