Some of the easiest things to source at a yard sale are some of the hardest to ship. A half-full bottle of designer perfume, a can of specialty spray paint, a vintage thermometer or a box of strike-anywhere matches can each look like profit and turn into a refused package. This manual explains how the U.S. Postal Service sorts those items and how to fit that into sourcing decisions. It covers domestic USPS mail only; other carriers and international mail have their own rules, and USPS rules change, so check the current pages linked below.
Three buckets: prohibited, restricted, ground only
USPS's shipping restrictions page sorts items into groups:
- Prohibited items are completely forbidden in the mail.
- Restricted items are allowed under certain conditions.
- Hazardous materials might be prohibited or restricted, and some can travel only by ground.
The page says every customer is responsible for reviewing USPS Publication 52 to find out whether an item is mailable, complying with postal regulations and U.S. law, and packing and marking packages as required. It also warns that knowingly mailing dangerous materials can lead to civil penalties of at least $250 and up to $100,000 per violation, plus cleanup costs and damages, and possibly criminal penalties.
Items USPS lists as prohibited domestically
The restrictions page lists these as items you cannot send in the U.S. mail:
- Air bags
- Ammunition
- Explosives
- Gasoline
- Liquid mercury
- Marijuana, medical or otherwise (hemp and CBD products are restricted rather than prohibited)
The mercury note matters for resellers of antiques. USPS says liquid mercury in any amount, and devices with a visible amount of mercury, such as antique thermometers, barometers, thermostats and switches, cannot be mailed. If you buy those, plan on local pickup or another lawful carrier that accepts them, or do not buy them.
Car parts deserve a second look too. An air bag module is on the prohibited list.
Restricted items a reseller is likely to meet
The restrictions page gives category notes. A few that come up in resale:
- Perfume. Perfume containing alcohol may not be shipped internationally or mailed domestically by air, but may be shipped within the United States by ground.
- Nail polish and glues. USPS says you are responsible for knowing the flashpoint and toxicity. Flammable versions may be mailed domestically if they are a consumer commodity, and some may only go by ground.
- Aerosols and gases. USPS lists mailable gases and aerosols with specific rules; read them before shipping spray products.
- Paint. Flammable or combustible paint is generally accepted within consumer commodity limits and packaging rules; water-based latex paint that is not flammable is not regulated as hazardous.
- Hand sanitizer, including wipes, must use USPS Ground Advantage or Parcel Select, and cannot go internationally.
- Safety matches must go by ground; strike-anywhere matches may not be mailed domestically.
- Lithium batteries in used devices must go by ground with specific markings. See shipping used electronics.
- Alcoholic beverages may not be mailed except in limited circumstances. USPS even advises removing alcohol logos from reused boxes so packages pass through the system.
Build the check into sourcing
The cheapest moment to discover a shipping restriction is before you pay. A short routine:
- Name the category in plain terms: "alcohol-based fragrance," "aerosol spray," "device with lithium-ion battery."
- Search Publication 52 and the restrictions page for it.
- Decide the path: normal, ground only, local pickup only, or pass.
- Price it with the right shipping. Ground transit is slower. If buyers in your category expect fast delivery, the restriction can affect demand, not just cost.
Write the result in your inventory notes. Next time you see the same category, you will not have to research it again.
Listings and promises
If an item can only go by ground, say so in the listing and quote a realistic delivery window. Do not offer an expedited option that would require air transport. Marketplaces may have their own restricted-item policies that are stricter than the carrier's; read them for each platform you use.
The FTC's mail order rule also expects sellers to have a reasonable basis for any shipping time they state. The manual on shipping time promises explains it.
Packing and drop-off
Follow the packaging instruction for the specific material. USPS says HAZMAT packages must be separated from other packages and presented in a container marked "HAZMAT," and it lists extra handling fees for some services and a noncompliance fee for commercial shipments that are improperly declared or labeled. Fees change; read the current page before you price.
If you are unsure, take the package to a Post Office counter before sealing it. USPS suggests that customers can take packages there to make sure they are labeled correctly.
When to pass
Pass when you cannot identify what the material is, when a flashpoint or battery rating is unknown and the item is not worth local-only sale, or when the item is prohibited. The items to avoid manual lists other categories that often cost more than they return.
Can I sell perfume online and ship it by USPS?
USPS says perfume containing alcohol may not be mailed domestically by air or shipped internationally, but may be shipped within the United States by ground transportation. Use a ground service, pack it to the Publication 52 requirements, and check the current rules before listing.