8 Things You Should Not Put in the Mail

The winter holidays are coming up, when even the most hardcore texters and emailers turn to the U.S. Postal Service to deliver greetings and packages. In 2022, the Postal Service processed more than 11.7 billion mailings and packages during the holidays, and on average, it took just 2.5 days to deliver those items to their destination.

But you can’t send just anything through the mail. Certain items are dangerous or illegal to ship, put the sender at financial risk, are only allowed with certain restrictions, or are just a bad idea. Some of those are obvious, but others may surprise you. Here’s a look at some of them.

1. Checks

It’s one of the oldest jokes out there – “the check’s in the mail.” But really, maybe that check shouldn’t be.

Reports of check fraud filed by banks nearly doubled to 680,000 in 2022, from 350,000 in 2021, according to the Financial Crimes Enforcement Network, which is part of the Treasury Department. Some thieves steal outgoing bills from mailboxes and use chemicals to erase the payee and amount, rewriting it for a new recipient and a larger sum. A cybersecurity expert told The New York Times that rather than mail checks, he recommends using electronic payment methods.

2. Cash and gift cards

Sending cash and gift cards through the mail is even riskier than sending checks. Mail theft, including by the people delivering it, has been an increasing issue. If someone snatches the birthday card you’re mailing to Cousin Annie with a stashed $50 or a Target gift card inside, it’s nearly impossible to track the stolen goods.

One tip: Many gift cards can now be sent via email.

3. Ammunition

While you can ship some firearms under certain conditions, the same is not true for ammunition.

Small-arms ammunition is categorized as explosive materials by the U.S. Department of Transportation and poses a danger to postal employees, equipment and customers. It’s a federal offense to send it via the U.S. Mail.

4. Alcohol

Alcohol can be a celebratory gift – a fine wine from France, a regional craft beer, a bottle of Champagne to honor a big day. But you’ll need to deliver it to your friend in person because intoxicating liquors having 0.5% or more alcoholic content are nonmailable, according to USPS.

5. Pets

Not sure why anyone would think it is safe to send Fluffy or Fido through the mail — or where they’d need to go — but think again. Cats, dogs, guinea pigs, hamsters, rabbits, mice, rats and squirrels are on the “not mailable” list, and for that, your furry friends thank you.

Birds and bees, however, can be mailable under certain conditions. Now, go imagine a porch pirate stealing a package of live bees.

6. Marijuana

Dude, just don’t. Even if marijuana is legal in your state, even if it’s for medical reasons, it can’t be legally sent through the mail. It is, however, OK to send hemp products that have a THC content of 0.3% or less.

7. Fireworks

Fireworks can be a blast — literally. They light up the sky on July 4th, New Year’s Eve and other celebrations. But you can’t pick up a box of the dazzlers at your local fireworks stand and mail them off to a friend.

As a video from the U.S. Postal Inspection Service points out, it’s easy to imagine the damage caused and danger to postal employees if such fireworks went off at any point in the mailing process. If fireworks are legal to buy and use where you live, enjoy them close to home.

8. Traditional thermometers

Ear and forehead thermometers, which use infrared scanners, are much easier to use than the old-fashioned, glass, hold-this-under-your-tongue version. But if you do have one of those vintage thermometers, they can’t be legally sent in the mail.

Old-style thermometers, as well as blood-pressure gauges and barometers, often contain liquid mercury, a hazardous substance that produces toxic vapors if exposed to air and can cause mercury poisoning if the vapors are inhaled. The risk of one breaking open somewhere along the mailing process is too great, so they’re not allowed.