People have sent everything imaginable through the mail, including bombs and anthrax. The U.S. Postal Service (USPS) restricts a variety of potentially dangerous items. The list of things you can't send in the mail includes non-murderous items such as meat and produce that are likely to spoil before arrival.
TL;DR (Too Long; Didn't Read)
You cannot send hazardous materials such as gasoline, poison or dynamite through the mails. Restricted items such as alcohol, firearms, cigarettes and knives are banned except in special cases. Perishable materials such as animals or food may be acceptable if you follow postal regulations and pack them properly.
Mailing Parcels — and Babies
In the 19th century, government mail didn't handle packages, leaving that up to private companies. In 1913, USPS launched parcel post, and things started getting weird. People became imaginative about using the new service; some parents shipped toddlers through the mail because it was cheaper than a railroad ticket.
Shortly after USPS parcels became a thing, the Beagles, a couple in Ohio, mailed their eight-month-old son a few miles to his grandmother for just 15 cents. They insured him for $50, just in case. Other parents followed their example.
It may sound insanely risky, but rural postal carriers were trusted government employees, a lifeline for small villages and isolated farms. Back in the day, putting a child in a mailman's hands seemed like a safe bet.
From Babies to Bombs
Babies weren't the only things sent through the mail in the early 20th century. In 1919, a wave of bombs arrived by mail at the offices of various politicians and millionaires, though most of them did not detonate. Many didn't even reach their destination due to insufficient postage, but a more successful set of "infernal machines" arrived through the mail a few weeks later.
The architects of the terror campaign were never caught or identified, though they were probably left-wing radicals. The government responded with raids, mass arrests and ruthless repression directed at anyone seen as subversive, including deporting some left-wing immigrants.
Murder by mail remains a thing, as it's easier to evade detection that way. Theodore Kaczynski, aka the Unabomber, began targeting victims with mailed bombs in 1978. He kept at it for 17 years, killing three people and injuring 24 before the FBI took him down.
Things You Can't Send in the Mail
The USPS says you can't mail anything that is "outwardly or of its own force dangerous or injurious to life, health or property." Mailing hazardous materials is a crime punishable by fines or imprisonment.
The second do-not-send category consists of items that are not hazardous but are restricted for some other reason. Shipping alcohol is banned with a few exceptions, such as cooking wine. The penalty for shipping alcohol or other restricted items via USPS can be up to a year in prison.
USPS no-mail regulations also cover perishable matter, defined as "anything that can deteriorate in the mail and thereby lose value, create a health hazard, or cause an obnoxious odor, nuisance or disturbance under ordinary mailing conditions." To mail perishables legally, you have to meet USPS packaging requirements and see that the mail arrives fast enough that the perishables don't spoil.
There's a persistent belief that cash is one of the things you can't send in the mail, but that's not true. It's perfectly legal to send cash to someone, just not a good idea. If you mail someone a $100 bill as a birthday gift, there's no refund or replacement if the letter never arrives.
Mailing money for criminal purposes, however, is just as illegal as if you handed over the cash in person. If someone mails cash to avoid taxes, launder money or buy drugs, for example, they face criminal penalties if they're caught.
Enter Our Contest to Win!
USPS says you also can't mail money to purchase lottery tickets. Postal rules define a lottery as a "scheme or promotion" in which you contribute money for a shot at a prize with the outcome determined entirely or partly by chance. Whether it's called a lottery, a raffle or something else, if there's a financial consideration, chance and a prize, it's illegal.
The USPS guidelines for mailing raffle tickets or lottery tickets are simple: Don't do it. Ads, flyers and announcements of lotteries or raffles are allowed as long as they don't include entry materials.
The rules make an exception for charity raffles that don't require a donation to enter. If using the ticket is free, it's acceptable to send it to you.
USPS rules divide hazardous materials into nine classes: explosives, gases, inflammable liquids, inflammable solids, oxidizing substances, toxic and infectious substances, radioactive materials, corrosives and miscellaneous. The rules here are the most restrictive. Most of these materials are prohibited with a few narrow exceptions.
To avoid legal trouble, you have to follow the federal definition of explosives, not what you might assume the definition is. If a customer wants you to mail fireworks or ammunition to them, for instance, tell them no. Those both qualify as non-mailable explosives. The mailable explosive list is small:
- Empty shotgun hulls, empty casings and casings without primer. These no longer qualify as explosives.
- Safety fuses.
- Toy propellant devices, such as a small rocket motor. The rules explicitly define what qualifies.
Restricted matter includes alcohol, guns, knives and tobacco products. This category also includes some items you might not expect. For example, USPS bans tools and equipment for staging animal fights as well as sending advertisements or promotions for animal fights through the mail.
Other restricted items are allowed as long as they're properly packaged:
- Cremated remains have to be sent priority mail express, be identified as cremains on the label, and conform to the packaging instructions on the postal service website.
- Mailing liquids, including creams, pastes and substances that may liquefy in transit, is legal if you package them according to regulations. If it's a hazardous material, you have to treat it according to the hazardous materials rules. Liquids that produce an obnoxious odor cannot be mailed legally.
Perishable items are a maybe for shipping, depending on what specifically you're shipping and whether you pack it properly. For example, if you're shipping animals, alive or dead:
- The packaging must protect the public and postal workers from diseased or dangerous animals.
- The packaging must protect against foul odors and noise.
- If you refrigerate a dead animal for shipping, you have to take steps to keep the refrigerant from melting and damaging your parcel or other pieces of mail.
- You have to protect live animals from dying of overheating, suffocation or lack of food and water. You cannot, however, include food and water in the package with them.
- It's illegal to mail plant pests.
- Injurious animals, such as those classed as invasive species, aren't mailable.
For other shipments in this category:
- Fresh food must be kept dry so that it doesn't spoil. The packaging must be sealed tight. If the food is dry but still likely to spoil en route to its destination, don't mail it.
- Eggs must be cushioned so that they don't break. You can't mail them legally if the shipment will be exposed in transit to harmful temperatures.
- It's legal to mail plants, except species covered by agricultural or conservation no-shipping rules. You can't mail marijuana, even if you're a medical marijuana supplier.
- USPS: Domestic Shipping Prohibitions & Restrictions
- USPS: Hazardous, Restricted and Perishable Mail
- Smithsonian: A Brief History of Children Sent Through the Mail
- Time: Mail Bombs Rocked American Politics a Century Ago. Here's What a Historian Thinks That Moment Has to Teach Us
- FBI: Unabomber
- Cornell Law School, Legal Information Institute: Injurious Articles as Nonmailable
- Snopes: Is Sending Cash By U.S. Mail Illegal?
- USPS: Lottery Matter
- USPS: Lotteries – Raffles