NC State University Mail Services



Mail of any kind for transport by the United States Postal Service should be enclosed in an appropriate envelope or parcel and sealed. The types of enclosures determine the mailing classification.


The following are examples of materials which should not be mailed in envelopes: 

Pens and Pencils
Paper Clips
Glass Chips
Metal Pieces

In general, any material which causes a bulge should not be mailed in an envelope. Such materials will not only jam or damage the mailing machines, but can also cause serious injury to Mail Services employees.
Foreign countries often have unique restrictions regarding enclosures. Check with the Mail Services Supervisor if in doubt.
In addition, the following are also classified as non-mailable and may be returned to sender:
Envelopes and Cards if these pieces are less than:

3 1/2 inches in height
5 inches in length
.007 inches in thickness
(thickness of a post card)


Enclosures, designed so that the address appears in a window envelope, must not be stapled to prevent slippage of the address from window view. If the address enclosure does not properly fit the window, use an envelope without a window. Please do not staple mail into envelopes. 

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