How stop tracking a file?

cg-rm does two things
   rm -f "$@"
   git-update-cache --remove -- "$@"

Does cg support a way to stop tracking a file without deleting it? 
The idea was to cg-init an entire directory (such as /etc/ or some
existing software project) and then selectivly stop tracking files,
such as *.o, selected binaries, ld.so.cache, etc. as they turned up.

thanks,

jeff