Drawback claims for postal exports must be filed via postal authorities; receipt or acknowledgement fixes the filing date. Exporters must label outer packing and deliver a prescribed claim to postal authorities; the date of receipt by the proper Customs officer is the operative filing date. If incomplete, Customs issues a deficiency memo within a prescribed period and, upon compliance within the subsequent prescribed period, issues an acknowledgement whose date is treated as the filing date. Drawback on postal exports is sanctioned by the respective Foreign Post Office.