I recently imported a very large translation file that had many empty translation strings. This caused my total translations (empty or not) from 3000 to 6000. This would not be a big deal, but I am using launchpad to translate the open source development of this project, and do not want to make people translate these useless strings.

I have a good backup of each of the translations before I did the import.

How can I clear all the translations and all the 'source' strings?