Sending a package through the mail can feel pretty routine. You pack the item, seal the box, add a label, and send it on its way. But some everyday products come with mailing restrictions that can catch people off guard.
The U.S. Postal Service handles hundreds of millions of mail pieces, so keeping hazardous, illegal, or improperly packaged items out of the system is a major safety concern. Some products are completely prohibited, while others can be mailed only by ground, in limited quantities, or with specific packaging and labeling.
The rules can also change based on the exact product, its ingredients, how much you’re sending, and where the package is going. Here are 22 items that deserve a closer look before you drop them at the post office.
Air Bags
Airbags may look harmless sitting in a vehicle, but they contain components that can trigger an explosive deployment. That puts them under hazardous-material regulations for shipping.
An airbag should never be tossed into an ordinary box and mailed like a household item. Eligible shipments require approved packaging, markings, and handling procedures. If you’re dealing with a replacement airbag or automotive parts containing an inflator, check the current USPS hazardous-material rules before attempting to ship it.
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Gasoline
Gasoline is one of the clearest examples of a household product that cannot simply be placed in a box and mailed. Its vapors are highly flammable, and even a small amount can create a serious fire hazard during transportation.
A container that previously held gasoline can also cause problems if it still contains flammable residue. If gasoline needs to be transported, use a carrier that is authorized to handle the material and follows the required hazardous-material procedures.
Marijuana
Marijuana laws can be confusing because individual states have legalized cannabis for medical or recreational use. Federal law still applies to the U.S. Postal Service, though, and that creates a major distinction.
Generally, marijuana cannot be mailed through USPS, even if it is legal in the state where the sender or recipient lives. State legalization does not automatically make an item legal to send through the federal mail system.
Aerosols
Aerosol cans include products such as spray paint, some cleaners, hairsprays, and certain personal-care products. Many contain flammable contents or compressed gases, which can make them hazardous during transportation.
Some aerosols can be mailed domestically under specific conditions, usually by ground service. Packaging must protect the can from damage and prevent leaks. Check the product’s label and the current USPS rules before mailing one.
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Alcoholic Beverages
Wine, beer, and spirits aren’t ordinary mail items. USPS generally prohibits consumers from mailing alcoholic beverages, with narrow exceptions for certain authorized shippers and purposes.
Private carriers may have their own rules, but that doesn’t mean every individual can put a bottle in a box and ship it. Licensing, age verification, packaging, and state laws can all come into play. If you’re shipping alcohol for a legitimate business purpose, check the carrier’s current requirements before sending anything.
Cigarettes, Cigars, and Tobacco
Tobacco products are subject to strict federal mailing rules. Cigarettes, smokeless tobacco, cigars, and related products don’t all have identical requirements, and a small number of exceptions exist for specific types of shipments.
Age verification and destination restrictions can also apply. International and military-address shipments may have additional rules. Anyone mailing tobacco should check the current USPS requirements instead of relying on general assumptions about what is permitted.
Cremated Remains
Cremated remains are one of the unusual items that USPS does allow people to mail, but the shipment has to follow special procedures.
USPS offers Priority Mail Express service for cremated remains, with specific packaging and labeling requirements. A secure inner container is needed, and the package must be marked appropriately. USPS also offers a specialized Cremated Remains Kit to help customers package these sensitive shipments correctly.
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Dry Ice
Dry ice is commonly used to keep food and other temperature-sensitive materials cold during shipping, but it isn’t treated like an ordinary packing material. As it changes from a solid to a gas, carbon dioxide needs a way to escape from the package.
USPS permits certain dry-ice shipments under specific conditions. The package needs appropriate markings, including the amount of dry ice being used. Restrictions also depend on the contents of the package and the transportation method.
Firearms
Firearms are heavily regulated in the mail, and the rules differ based on the type of firearm and who is sending and receiving it.
Federal law and USPS rules place strict limits on firearm shipments. Licensed dealers and manufacturers have different mailing privileges from private individuals, while state and local laws can add further restrictions. Ammunition is also subject to separate rules.
Because the consequences of an improper shipment can be serious, check the current federal and USPS requirements before attempting to mail any firearm.
Adhesives
Glue doesn’t automatically mean “safe to mail.” Some adhesives contain flammable solvents or other hazardous ingredients that put them under hazardous-material rules.
Small quantities of certain consumer adhesives may qualify for domestic ground shipping, while industrial products can face additional restrictions. The product’s safety label and flash point matter, so check the exact adhesive rather than assuming all glue products are treated the same way.
Hand Sanitizer
Hand sanitizer became a common household product, but many formulas contain enough alcohol to make them flammable. That means certain sanitizers are regulated as hazardous materials for mailing.
Eligible sanitizer shipments generally have to travel by surface transportation and meet USPS packaging and quantity requirements. International shipments and some special destinations can have different restrictions. Check the product information and current USPS rules before sending bottles through the mail.
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Hemp Products
Hemp-derived products can be mailed in certain circumstances, but there are important limits. Under federal law, hemp and products derived from hemp generally must contain no more than 0.3% THC by dry weight, with additional requirements depending on the product.
The sender is responsible for being able to demonstrate that the shipment complies with applicable law. State rules can also differ. International and military-address shipments may face additional restrictions, so a product that can legally be mailed domestically may not be eligible for every destination.
Lithium Batteries
Lithium batteries are found in phones, cameras, laptops, power banks, and plenty of other household electronics. Their mailing rules exist because damaged or improperly packaged batteries can short-circuit and catch fire.
Some lithium batteries can be mailed domestically if they meet requirements for quantity, packaging, labeling, and transportation. Damaged, defective, or recalled batteries have much stricter rules. International shipments also face additional restrictions.
Before mailing a battery by itself or inside an electronic device, check the battery type and the current USPS requirements.
Live Animals
Believe it or not, USPS does allow certain live animals to be mailed under tightly controlled conditions. Bees, poultry, and some other animals may qualify, but each type has its own requirements.
Packaging needs to provide adequate ventilation and protect the animals during transit. Many household pets cannot be mailed through USPS. Anyone sending live animals must follow the applicable packaging, timing, labeling, and transportation rules.
Matches
Matches are another household item with mailing restrictions. Safety matches can be mailed domestically by ground when properly packaged, but strike-anywhere matches are prohibited.
The difference comes down to how easily the match can ignite. Safety matches require a deliberate striking surface, while strike-anywhere matches can ignite through friction with other surfaces. International mailing of matches is generally prohibited.
Medicines and Prescription Drugs
Prescription drugs aren’t treated like ordinary packages. Federal law places restrictions on who can mail certain medications, particularly controlled substances.
Licensed pharmacies, manufacturers, medical professionals, and other authorized parties may have mailing privileges that aren’t available to individual consumers. Some medications can be mailed by patients under specific circumstances, while others cannot.
International shipments can be even more complicated because the destination country’s laws also apply. Check the applicable USPS and federal requirements before sending medication.
Mercury
Liquid mercury is prohibited in the mail because of its toxicity and the hazards created by spills.
Some mercury-containing devices may qualify for mailing under specific conditions. Old thermometers, barometers, and similar items need special attention because their contents can vary. If you’re unsure what a particular item contains, check the rules before packing it.
USPS Publication 52 provides detailed information about hazardous, restricted, and perishable materials.
Nail Polish
That little bottle of nail polish in your bathroom cabinet can contain flammable solvents. Because of this, many nail polishes are treated as hazardous materials for shipping.
Eligible nail polish shipments generally have to travel by ground and meet packaging requirements that prevent leaks. International shipping is much more restrictive. Before mailing several bottles, check the product’s label and the current USPS rules.
Paint
Paint comes in many different formulas, and the mailing rules depend on what’s inside the can. Some paints contain flammable ingredients, while water-based paints generally present fewer shipping concerns.
Paint shipped through USPS needs suitable leak-proof packaging and may require hazardous-material markings. The product’s flash point and classification determine which rules apply.
The old ORM-D labeling system has also been phased out, so older advice that tells you to use an ORM-D marking may be outdated. Always check the current requirements before shipping paint.
Perfume
Perfume can be surprisingly tricky to mail because many fragrances contain alcohol. Alcohol-based perfumes can be flammable and are subject to hazardous-material restrictions.
Certain eligible perfumes can be shipped domestically by ground, provided they meet USPS requirements for packaging, quantity, and labeling. Air transportation is generally restricted for these products. International shipments can have additional prohibitions.
A leak-proof package is especially important because a broken perfume bottle can damage other mail pieces.
Perishable Items
Perishable food isn’t automatically forbidden, but sending it requires more planning than mailing a box of books. Fresh food can spoil, leak, or become unsafe if it spends too long in transit.
USPS allows certain perishables, but the sender takes responsibility for packaging the item properly and selecting an appropriate delivery service. Insulated packaging, cold packs, or other temperature-control materials may be needed for certain foods.
Before shipping meat, seafood, dairy products, or other temperature-sensitive goods, check the current USPS guidance and consider how long the package may spend in transit.
Poisons
Some poisonous or toxic substances are restricted or prohibited from the mail. Others may be eligible for domestic shipping if they meet very specific hazardous-material requirements.
The exact chemical, concentration, packaging, quantity, and transportation method can all affect whether a substance is mailable. A generic warning such as “poison” isn’t enough to determine the rules.
If a product is labeled toxic, poisonous, corrosive, or otherwise hazardous, check its safety information and the current USPS requirements before putting it in the mail. When the rules aren’t clear, ask USPS or use a carrier that is authorized to handle the material.
