Prohibitions 49
Aperture envelope. A packet enclosed in an aperture envelope, that is, an envelope with an open (cut-out) panel which does not conform to the following conditions:
The open (cut-out) panel must not exceed 33 inches in length by 14 inches in width;
༥.
The requirements shown in (1). (2), (3) and (4) in the preceding paragraph headed Window envelope;
3. A minimum space of at least half an inch must be left between the sides and base of the cut-out panel and the respective edges of the envelope.
Transparent envelope, A packet enclosed in a wholly transparent envelope.
"Trap" packets. A packet having an opening large enough to entrap small letters or postcards. A small envelope not more than 34 inches in depth with a tuck-in flap along the top not exceeding 6 inches in width may be used in the open post. An envelope exceeding that depth must not have an opening of more than 44 inches in width. If a large envelope is necessary, senders should adopt a pattern having a special kind of flap which can be adjusted so as not to leave a large opening; or the packet can be fastened with string provided that it can be easily untied. If metal paper fasteners (paper clips are inadmissible) are used, they must be blunt and must be well pressed down to obviate risk of injury to the hands of the Post Office staff.
The maximum size for a folder is 6 inches in length by 34 inches in width.
Dimensions and shape. A pictorial card or packet containing a collection of views of places, which does not conform to the following conditions :-
It must not be less than 4 inches in length by 24 inches in width, and must, when- ever possible, be square or oblong in shape. If the card is irregular in shape, the lower edge and the left-hand edge should be straight and at right angles to one another, but those edges may be serrated provided that the packet will stand upright upon them when sorted with other articles;
A card, envelope or folder which is less than 4 inches in length by 24 inches in width or a packet of such small dimensions as to be likely to impede the officers of the Post Office in dealing with it.
Postcards and other cards sent unenclosed, must not be less than one-hundredth of an inch thick.
Re-use of envelopes. An envelope which has previously been used for postal pur- poses unless it has been suitably reconditioned by completely covering all the old postage stamps, stamp impressions and addresses (including the address of the sender if no longer relevant) with gummed white slips which must be well stuck down. Used registered envelopes must not be re-used for the unregistered post unless they are covered both back and front with suitable adhesive paper in such a way as to hide effectively all marks. Particulars of the conditions governing the re-use of envelopes for the registered post are given under the heading "Registration Stamps in payment of fresh postage must always be affixed along the top of the reconditioned envelope at the right-hand corner on the same side of the new address in a position convenient for datestamping,