No-orientable surfaces

Hello everyone. I have a problem with no.orientable surfaces. These are the strip of Móbius, the surface of Klein, the one of Boy and the two of Steiner: Crosscap ad Roman surfaces. This topology gets pretty bad for use in CAD programs, since they are "in and out" at the same time. Generate naked edges and non-manifold edges.
The problem itself is when I make an offset of the surfaces, which create "bad objets" in Rhino. I'm using Mantis, a plugin for Mathematica software, and one based on this the Math Surfaces script from http://www.co-de-it.com/wordpress/code/grasshopper-code.
Both give me errors. I have tried to make a merge with the normal flip in the same model, but the error continues. If I do a split, in Rhino, there is no problem to create a solid offset, but the opposite is totally different if I make a Mirror.
Can you help me with this complicated issue?
Thank you.