"Deleting" flipped Faces crossing correctly-flipped Faces (how?)

Hello everyone! :slight_smile:
I really don’t know what to do with this cube/mesh…
(I’m running Blender v2.77)

I can’t say my problem in words (because I’m german), but some images can say more than words! :slight_smile:
Anyway, I want that these “Edges”:

Will be like this:

How can I “erase” them without affecting the other side? The sides are IDENTICAL.

Can someone help me? I really don’t know how to do this… :frowning:

untitled.blend (522 KB)

Hi there!

your problem was that you have some overlapping faces i just pulled them back. Here is a blend file http://www.pasteall.org/blend/42563
You should also know that ngons are not your friend, they will bite you in the long run. :wink: