6 things you can’t mail, according to U.S. Postal Service (2024)

Millions of Americans are getting holiday packages ready to send. There are some things you need to know, however, to prevent issues with mailing some types of products.

And while the chances of you sending firearms or fireworks through the mail are likely low, there are some other things, including common household items, that are prohibited from entering the mail system, according to the U.S. Postal Service.

Here are 6 of those items:

Ammunition

Small arms ammunition is categorized as explosive materials by the U.S. Department of Transportation and, under federal law, it’s illegal to send ammunition via the U.S. Mail. Ammunition that is designed to be fired from a pistol, revolver, rifle, or shotgun, as well as primers and blank cartridges - including those designed for tools- and propellant powder for use in any firearm, is prohibited from mailing. Small arms ammunition poses a danger to postal employees, equipment and customers, USPS said, and violating the law could make you subject to civil penalties and criminal charges.

Firearms

The Gun Control Act of 1968, along with postal regulations, highly regulates the shipment of firearms. Generally, handguns are prohibited in the U.S. Mail. There are exceptions for licensed dealers and other regulations that you can see here.

Fireworks

Want to send someone some fireworks for New Year’s Eve? That’s fine – but you can’t send them in the U.S. mail. Fireworks can pose a significant hazard while in air transportation, endangering the lives of postal employees and the traveling public.

Mercury

Liquid mercury – either on its own or contained in various items - is prohibited in the mail. It’s a hazardous substance that produces toxic vapors if exposed to air and can cause mercury poisoning if the vapors are inhaled. Older-style thermometers, blood pressure gauges, and barometers — which often contain liquid mercury– may become damaged or broken during the shipping process, making them all off-limits for mailing.

Household items

This is where things can get tricky. There are other items that are used for everyday activities around the house that can pose a significant risk during transportation and are considered hazardous materials.

Some of those common items that you might not think of include flammable aerosol products (spray disinfectants, spray paints, and hairspray), lithium batteries, safety matches, perfume, and cosmetic products such as nail polish and nail polish remover. Although some of these materials are allowed to travel through the mail, there are strict quantity limits, packaging, and marking requirements. Additionally, some items are not allowable by airmail but may be sent via ground delivery only.

Lithium batteries

Lithium batteries power all sorts of electronics from cell phones, laptops and tablets to wireless headphones, toys and portable toys. These batteries, however, are considered hazardous materials and remain highly regulated in transportation, USPS said.

When improperly prepared and shipped, packages containing lithium batteries are prone to catch fire and possibly explode during handling. When correctly prepared, declared, and shipped in quantities below the USPS threshold, these risks can be reduced and avoided. It is also important to note that larger lithium batteries such as those needed for e-bikes, scooters, and electric cars are prohibited from being mailed at all.

Important to remember

Postal employees will ask people with packages if they contain perfume, aerosols, lithium batteries, mercury and other hazardous materials. Some people aren’t aware of the regulations while others purposely try to get around them. Either way, the outcome of shipping these dangerous items can have extremely dangerous or fatal consequences. If an incident occurs in which improperly prepared or undeclared items have been intercepted or encountered, legal consequences, including criminal charges and civil penalties, can be sought against the person sending or receiving the package.