With CheckedListBox1
 
    'Liste von hinten durchlaufen
    For i As Integer = .Items.Count - 1 To 0 Step -1
        'Ist das Item i gechecked
        If .CheckedItems.Contains(.Items(i)) Then
           'Item i entfernen
           .Items.RemoveAt(i)
        End If
    Next i
 
End With