Sub RemoveDupes()
Dim Cl As Range
Dim Rng As Range
Set Rng = Range("J" & Rows.Count).End(xlUp).Offset(1)
With CreateObject("scripting.dictionary")
For Each Cl In Range("J2", Range("J" & Rows.Count).End(xlUp))
If Not .exists(Cl.Value) Then
.Add Cl.Value, Nothing
Else
Set Rng = Union(Rng, Cl)
End If
Next Cl
End With
Rng.EntireRow.Delete
End Sub