Rather more efficient:
Sub Demo()
Application.ScreenUpdating = False
With ActiveDocument.Range.Find
  .ClearFormatting
  .Replacement.ClearFormatting
  .Format = False
  .Forward = True
  .Wrap = wdFindStop
  .MatchWildcards = True
  .Text = "[" & ChrW(&H1000) & "-" & ChrW(&H109F) & "]"
  .Replacement.Text = ""
  .Execute Replace:=wdReplaceAll
End With
Application.ScreenUpdating = True
End Sub