Eliminate Proxy objects from .dxf files

I am using a proprietary SW to read dxf files.
One of my customers that uses AutoCAD 2006 Mechanical, sends me DXF
files that contain proxy information.
If I load the dxf file to the same AutoCAD version and save it, I get
a clean DXF file with no proxy information.

My questions are

1) What do I need to tell my customer to change in his AutoCAD setup
so that no proxy information will be created.
2) Is there a batch utility that convert Proxy data to standard lines,
arcs, circles, etc.

Thanks, Dan Tishcler