..for when you import/merge models and end up with multiple copies of materials..
Can you provide a sample file and tell me if you're using a rendering plugin other than Rhino Render? I don't see this here so I think it has to do with a specific material definition from a plugin. The Purge command might help you though as it allows for the purging of unused materials via a command line option.
Huh..Can't get this to repeat on the file I (thought I) saw it in.Could be me, of course...
Thanks Brian for looking at all my worries.. I'll try to be a bit more rigorous in future.
No problem... there are bunch of interconnecting pieces here when using Neon and the active render plugin is one. Material definitions are as you probably know not universal so that was the first thing that came to mind.