Desproteger hojas de calculo en excel

Aqui les pongo una rutina que funciona para reventar claves de bloqueo en excel, de hecho la clave que consigue no es la original pero funciona:

Sub breakit()

 Dim i As Integer, j As Integer, k As Integer
 Dim l As Integer, m As Integer, n As Integer

   On Error Resume Next
   For i = 65 To 66
    For j = 65 To 66
     For k = 65 To 66
      For l = 65 To 66
       For m = 65 To 66
        For i1 = 65 To 66
         For i2 = 65 To 66
          For i3 = 65 To 66
           For i4 = 65 To 66
            For i5 = 65 To 66
             For i6 = 65 To 66
              For n = 32 To 126

   ActiveSheet.Unprotect Chr(i) & Chr(j) & Chr(k) & _
    Chr(l) & Chr(m) & Chr(i1) & Chr(i2) & Chr(i3) & _
    Chr(i4) & Chr(i5) & Chr(i6) & Chr(n)

   If ActiveSheet.ProtectContents = False Then
    MsgBox "One usable password is " & Chr(i) & Chr(j) & _
       Chr(k) & Chr(l) & Chr(m) & Chr(i1) & Chr(i2) & Chr(i3) _
       & Chr(i4) & Chr(i5) & Chr(i6) & Chr(n)
    Exit Sub
 End If
             Next
            Next
           Next
          Next
         Next
        Next
       Next
      Next
     Next
    Next
   Next
  Next

End Sub

Copiar esta rutina en un módulo del mismo libro y ejecutarla. Eso es todo.