How to dissolve a "mirror default" config from an assembly?

As a general rule we try not to use mirrored parts because they usually don't work as expected.  I used them to avoid creating extra work, but now I have a "mirrored default" configuration in each of my two parts as well as the assembly.  How do I undo this?  I would prefer these extra configs are not in my parts. 

Thanks,

Michael

SolidworksAssemblies