A family of Microsoft presentation graphics products that offer tools for creating presentations and adding graphic effects like multimedia objects and special effects with text.
In Windows version you can use Inspect Document to do this but this is not available on the Mac version. Maybe someone with a PC could help?
You should be able to do this with a little code on a Mac though. This code depends on the notes being in Shape2 (the default) - Test on a copy. If the notes are not in Shape2 you might need to make it a little more complex
Sub Zap()
Dim osld As Slide
For Each osld In ActivePresentation.Slides
With osld.NotesPage.Shapes(2)
If .HasTextFrame Then
.TextFrame.DeleteText
End If
End With
Next osld
End Sub