I'm not sure if I'm missing something very obvious, but having skimmed the documentation, FAQ and discussions I still can't figure out if I can remove all faces from a photo manually.

As it stands, all I can do is replace a face with another one, but not remove all of the faces?

Arguably, it could be a face, but it's not. It's a pattern on a table :). I'd like to permanently remove the "face" tag but I can't figure out how to accomplish that.