At any time before the expiration of eighteen months after the qualification in this Commonwealth of any executor of the will or administrator of the estate of any nonresident decedent, such executor or administrator shall file with the clerk of the court in which he qualified proof that all death taxes, together with interest or penalties thereon, which are due to the state of domicile of such decedent, or to any political subdivision thereof, have been paid or secured or that no such taxes, interest or penalties are due, unless it appears that letters have been issued in the state of domicile. Such proof may be in the form of a certificate issued by the official or body charged with the administration of the death tax laws of the domiciliary state.