If you are sending postcards, be aware that the minimum size is 3.5 x 5 inches. So a small photograph with a stamp on the back will not count even if addressed properly. All mail must be at least .007 inches thick. So if you send a sheet of regular paper as a postcard, it would be too thin. When mail pieces get too small or flimsy they are just too easy to lose or damage during handling, so those types of postcards or envelopes are considered unmailable.
If you are mailing overstuffed letters or home-made cards, be aware there is a limitation on the thickness of the envelope. A standard size card that is too fat (over ¼ inch) or too irregular in thickness will not go through automated processing equipment and will need to be processed by hand. This can cost a bit more than your standard letter to send even though the card may be well within the weight limit for the standard amount of postage. The most economical solution is to take all of your cards at once to the post office and have them check the thickness and assign the postage or if you only have one card and want to avoid that hassle, you could double stamp your envelope.
Also watch for loose items within your letter like pens, beads, keys or coins. Not only can these make your letter thickness uneven, they can cause a paper envelope to tear and drop its contents and are therefore sometimes considered unmailable. The post office doesn’t want to deal with the contents of your envelope falling out all over the place or stabbing someone while the envelope is in transit. If you need to send items like those mentioned before, consider taping them to a piece of paper and wrapping it up so they can’t move around within the envelope.
Here are a few other non-machineable (higher priced and more risky to send) types of mail:
- Envelopes with clasps, buttons or strings to close the envelope (these can get snagged with other pieces of mail very easily).
- Envelopes wrapped in plastic or envelopes that are not made of paper on the outside.
- Envelopes that don’t bend
- Custom envelopes which are too square or too elongated
- Envelopes or postcards that are addressed sideways- sometimes considered non-mailable (there must be a minimum 5 inch length of the envelope or postcard where the recipient name and address are written, regardless of whether the address takes up that much space or not)
- Envelopes that are stamped and addressed creatively may also be considered unmailable
If your parcel weighs over 13 ounces (slightly more than the weight of a typical can of soda), there are special security precautions that will apply. This is to help ensure that your postal workers and airline passengers are safer. Parcels over 13 ounces (with only stamps as postage) must be brought to an employee at the Post Office counter. Stuffing your parcel into a mail collection box, leaving it on a counter or elsewhere about the Post Office will get it returned to you, even if everything else with the parcel is in order. You can also not expect that package will be picked up by your mail carrier if you leave it in your mailbox. So how do you avoid going to the Post Office? Answer: These rules apply only to parcels that use regular stamps as postage. Postage on a parcel that was created by a service like Stamps.com® or by a postage meter will allow you to get the parcel picked up from your home or office without having to go anywhere. We speculate this is because it makes the sender‘s information much easier to confirm.
Recycling helps save money and reduce waste, but there are some USPS rules regarding reuse. If you reuse packaging or boxes, you need to completely obscure any previous markings (not just draw a line through) and remove any old labels. Make sure there aren’t any old indicators of hazardous or restricted materials. An easy example would be to try to send gifts in a box that is labeled by a vineyard. This can get a parcel refused, regardless of what its actual contents are.
By law, it is considered the mailer’s responsibility to make sure that they do not send unmailable materials by mail. It is also the mailer’s responsibility not to transmit material via mail which is not legally transferrable.
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