You can uninstall or removes an installed ia32-libs-i386 package itself from Debian 7 (Wheezy) through the terminal,
$ sudo apt-get remove ia32-libs-i386
If you would like to remove ia32-libs-i386 and it's dependent packages which are no longer needed from Ubuntu,
$ sudo apt-get remove --auto-remove ia32-libs-i386
If you use with purge options to ia32-libs-i386 package all the configuration and dependent packages will be removed.
$ sudo apt-get purge ia32-libs-i386
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 ia32-libs-i386