Cleaning Mathematica notebooks for inclusion in git repositories

Update: The SaveReadableNotebook resource function provides a more complete solution to this problem and is recommended instead of the below.

The following function can be run to clean parts of a Mathematica notebook which make it difficult to maintain in version control.

CleanNotebook[file_] := Module[{nb, contents, newcontents},
   nb = NotebookOpen[file];
   SetOptions[nb, "TrackCellChangeTimes" -> False, 
    PrivateNotebookOptions -> {"FileOutlineCache" -> False}];
   contents = NotebookGet[nb];
   newcontents = 
    contents /. {(CellChangeTimes -> _) -> 
       Sequence[], (CellTags -> _) -> Sequence[]};
   NotebookPut[newcontents, nb];