(1)Unregistered postcards and letter cards which cannot be disposed of under section 38 of the Act shall be detained for a period of 72 hours, on the expiration of which they may be destroyed.Provided that postcards and letter cards, other than those sent "Service Unpaid" under the provisions of rule 186 on which the postage has not been prepaid shall be destroyed forthwith.(2)Registered postcards and letter cards shall be detained for a period of three months and then destroyed.
