You can uninstall or removes an installed aumix-gtk package itself from Ubuntu 16.10 (Yakkety Yak) through the terminal,
$ sudo apt-get remove aumix-gtk
If you would like to remove aumix-gtk and it's dependent packages which are no longer needed from Ubuntu,
$ sudo apt-get remove --auto-remove aumix-gtk
If you use with purge options to aumix-gtk package all the configuration and dependent packages will be removed.
$ sudo apt-get purge aumix-gtk
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 aumix-gtk