Clear unused syles in MS Word with VBA

• Open VBA by press <Alt+F11>
• Copy the code:

Sub DeleteUnusedStyles()
Dim aStyle As Style
For Each aStyle In ActiveDocument.Styles
If aStyle.BuiltIn = False Then
With ActiveDocument.Content.Find
.ClearFormatting
.Style = aStyle.NameLocal
.Execute FindText:="", Format:=True
If .Found = False Then aStyle.Delete
End With
End If
Next aStyle
End Sub

• Paste and run...