Can I mail it by USPS? Publication 52, item by item

By The Reseller Index · AI-drafted from official sources · Updated Oct 31, 2026 · How we make this page

12 of these 17 items can be mailed inside the US, 11 of them only if you meet a condition, such as a packing rule, an amount limit, a ground-only label, an Adult Signature or a Post Office counter visit. Mercury thermometers and barometers, car batteries with liquid acid, liquor and vapes are nonmailable, and switchblades go only to the buyers Publication 52 lists.

Each row gives the rule in USPS's words with its section of Publication 52 (August 2026 edition, which replaced the February 2026 one), then what to do. Items with a page of their own on this site, such as perfume, matches and lithium batteries, are listed after the table with a link.

Publication 52 read on Oct 31, 2026

Item by item: what Publication 52 says

17 items from USPS Publication 52 (August 2026 edition), read Oct 31, 2026. Section numbers link to the rule on USPS's Postal Explorer.
Item	Verdict	Publication 52 says	What to do
Mercury thermometer, barometer or blood-pressure gauge	Nonmailable	“Mercury and Mercury-Containing Devices (UN2809): Includes metallic mercury and items such as thermometers, barometers, and sphygmomanometers (i.e., blood pressure meters) that contain metallic mercury.” (Publication 52, 348.21)	USPS won't carry one to any address: metallic mercury, and any device that holds it, is on Publication 52's list of nonmailable corrosives. USPS's own restrictions page adds that liquid mercury is barred in any amount, and so is a device with a visible amount of it (USPS).
Compact fluorescent bulb (CFL) or another device with a trace of mercury vapor	Mailable with conditions	“Compact Fluorescent Lamps (CFL) and similar consumer devices containing minute amounts of mercury are mailable by air or surface only when each device, article, or apparatus contains 100 milligrams (mg) (0.0035 ounce) or less of mercury” (Publication 52, 348.22(g); Packaging Instruction 8C)	One package may hold no more than 1 gram of mercury in all, so at most 10 devices at the 100 mg limit go in one box (348.22(g)). Cushion and separate each device in noncombustible absorbent material inside a strong outer box, and mark it “Manufactured Devices Containing Less Than 100 mg Mercury”; by ground it also needs the Limited Quantity surface mark, and by air more marks and a Shipper's Declaration (Packaging Instruction 8C). Not to other countries: Packaging Instruction 8C prohibits international mail.
Car, motorcycle or other lead-acid battery with liquid acid	Nonmailable	“Batteries with Liquid Electrolyte (UN2794, UN2795): Includes automobile lead acid batteries, except for the non-spillable type permitted under 348.22.” (Publication 52, 348.21)	A wet lead-acid battery can't be mailed. The one lead-acid type Publication 52 allows is the sealed nonspillable kind in the next row.
Sealed nonspillable lead-acid battery (UN2800)	Mailable with conditions	“Nonspillable Wet Batteries (UN2800): Acceptable if completely sealed to prevent the liquid corrosive from spilling during handling and prepared per Packaging Instruction 8B in Appendix C.” (Publication 52, 348.22; Packaging Instruction 8B)	One battery per package, protected from short circuits, surrounded by noncombustible material that can absorb all of its liquid, in a strong fiberboard box; the package may weigh no more than 25 pounds and is marked “NONSPILLABLE BATTERY” on the address side (Packaging Instruction 8B). Inside the US only, by air or ground: Packaging Instruction 8B prohibits these batteries in international mail.
AA, AAA, C or D batteries, loose or inside a toy or remote	Mailable	“Household Dry-Cell Batteries: Common household battery types (AA, AAA, C, D, etc.) are generally not regulated as hazardous materials and are mailable.” (Publication 52, 348.22)	Pack them under the general packaging rules in DMM 601, as 348.22 says. Lithium batteries are not in this row: 348.22 sends them to the lithium rules in 349.2, which are on spare lithium batteries and used phones and laptops.
Vacuum tubes and other electronic tubes for radios, amplifiers and TVs	Mailable with conditions	“Electronic Tubes: These items are mailable without restriction if the volume does not exceed 30 cubic inches and the tube is charged with gas at 35 psig or less.” (Publication 52, 342.22)	A tube that fits inside a 2 × 2 × 6 in. space has a volume of 24 cubic inches at most, 6 under the 30-cubic-inch line; with a gas charge of 35 psig or less it ships in a strong outer box under DMM 601 (342.22). A bigger tube, or one charged above 35 psig, is outside that line: ask USPS for a mailability ruling before you list it (Publication 52, 215).
Knives, razor blades and other sharp tools	Mailable with conditions	“All sharp-pointed or sharp-edged instruments (e.g., knives, tools, ice picks, razor blades) that are otherwise mailable must be securely packaged in a strong container.” (Publication 52, 443.1)	Use enough cushioning that points and edges can't cut through the outer box in handling; USPS recommends an inner and an outer container (443.1). Automatic knives are the next row. State and local knife laws still count: for restricted matter, Publication 52 makes the mailer responsible for meeting the federal and state laws and local ordinances that apply to the shipment (412). To another country, a knife you can mail at home goes only where that country's listing in the International Mail Manual allows it (Publication 52, 633); each of the site's country pages links that country's listing.
Switchblade or other automatic knife	Restricted	“A switchblade knife, as defined in 441.2, is mailable only to the following categories of addressees” (Publication 52, 442; 443.2)	Those addressees are government supply and procurement officers (federal, armed forces, National Guard or militia, state, county or city), and manufacturers or dealers may mail to them for official procurement or resale; a private buyer is not on the list (442). Publication 52 counts a knife as a switchblade when its blade opens automatically by a button or other device on the handle, or by inertia, gravity or both (441.2). If you aren't sure about yours, 442 says a ruling may be requested from the local postmaster. A permitted mailing carries no marking of any kind that shows what is inside (443.2).
Dry ice packed with food or another item it keeps cold	Mailable with conditions	“Domestic Mail via Air Transportation: Dry ice is permitted in quantities of up to 5 pounds per mailpiece.” (Publication 52, 349.32; Packaging Instruction 9A)	Hazmat sent as Priority Mail has to meet the air rules whatever route it takes (327.12), so a box with 6 lb of dry ice, 1 lb over the air limit, goes by Ground Advantage, not Priority Mail, marked “Surface Only” or “Surface Mail Only” and “Dry Ice, UN1845”; by surface there is no 5 lb cap (9A). By Priority Mail (5 lb or less), the box needs a Class 9 label, the “Dry Ice, UN1845” marking and a Shipper's Declaration for Dangerous Goods in triplicate (Packaging Instruction 9A). Every box must be vented so the gas can escape, and its address side shows what the dry ice is cooling and the dry ice's net weight; dry ice is mailable only as a refrigerant for something that is itself mailable (349.32, 9A). Not to other countries (349.32), and not to APO, FPO or DPO addresses or to U.S. territories outside the customs territory either (Publication 52, 743).
Liquor, wine or beer, a sealed collectible bottle included	Nonmailable	“Intoxicating liquors and taxable liquors, including those obtained under a prescription or as a collector's item, are nonmailable.” (Publication 52, 424; 421)	Publication 52 defines intoxicating liquor as a beverage of 0.5 percent or more alcohol by weight that is taxable under Chapter 51 of the IRS code (421), and the ban is federal law, 18 U.S.C. 1716 (424). A sealed vintage bottle sold to a collector is no exception: the rule names collector's items. USPS's restrictions page puts beer and wine under the same ban as liquor, except in limited circumstances, and for those it links Publication 52, 422 (USPS): products that aren't drinks (the next row) and liquor mailed between federal or state agency employees for official use (422.22). Reusing a wine or liquor box? Its alcohol labels and logos have to go first: reusing boxes.
Cooking wine, mouthwash, cold remedies and other products with alcohol that aren't drinks	Mailable with conditions	“Examples of these mailable products include cold remedies, cooking wine, and mouthwash.” (Publication 52, 422.21)	The product must comply with IRS and FDA regulations and be neither a taxable alcoholic beverage, nor poisonous, nor flammable (422.21). A flammable one is outside this row: check its Safety Data Sheet against the flammable-liquid limits on perfume, nail polish and aerosols.
Air rifles, BB guns, pellet guns and paintball guns	Mailable with conditions	“Shipments containing air guns with a muzzle velocity of 400 or more feet per second (fps) must include an Adult Signature service per DMM 503.8.” (Publication 52, 432.3; 432.2)	An air gun that can be concealed on a person needs Adult Signature at any speed (432.2). Adult Signature is bought with the postage on a label you make online, such as Click-N-Ship or PC Postage (DMM 503.8.2): $9.70 for Adult Signature Required, $10.00 for Restricted Delivery (Notice 123). Worked totals are below the table. An air gun built on the frame or receiver of a real firearm is regulated as a firearm, and a package with compressed air in it follows the gas rules in 342 (431.7). State and local rules apply too: Publication 52 leaves them to the mailer (432.2, 432.3).
Replica or inert grenades, shells and other dummy explosives	Mailable with conditions	“Replica or inert explosive devices that are not dangerous but resemble explosive devices (i.e., simulated grenades) are mailable provided all following conditions are met” (Publication 52, 434)	All three: you present the package at a Post Office retail counter, it goes by Registered Mail, and its address side is labeled “REPLICA EXPLOSIVE” in letters at least 1/4 inch high (434). What Registered Mail adds: Registered Mail fees.
Loose powders: eyeshadow, pigment, protein powder	Mailable with conditions	“Powders must be packed in sift-proof containers or other containers that are sealed in durable sift-proof outer containers.” (Publication 52, 451.2)	The rule covers dry materials that could cause damage, discomfort or soiling if they leak (451.1). A powder that is corrosive, explosive, flammable, toxic or otherwise hazardous follows the hazmat rules in Publication 52 chapter 3 instead (451.21). Creams and pastes go with liquids: 451.3 holds nonhazardous liquids, creams and pastes to the same packing rules (shipping liquids).
Vapes, e-cigarettes and their pods, tanks, liquids and parts, nicotine-free included	Nonmailable	“Any reference to ENDS includes any component, liquid, part, or accessory of an ENDS device, regardless of whether they are sold or provided separately or contains or is used with nicotine.” (Publication 52, 471; 472.1)	These are nonmailable unless an exception in 473 applies (472.1). The exceptions are shipments that stay within Alaska or within Hawaii (473.2), licensed businesses and government agencies USPS approves (473.3), individual adults mailing small amounts for noncommercial purposes (473.4), consumer testing (473.5) and public health (473.6). Every exception needs a face-to-face hand-over to a Postal Service employee at a retail or business mail counter, never a pickup, a drop box or an approved shipper location, and none covers APO, FPO or DPO addresses or mail to other countries (473.1). A gift between adults is noncommercial, but Publication 52 says gifts do not include products bought from a vendor for someone else by mail order (473.42).
Essential oils and fragrance oils	Mailable with conditions	“A liquid with a flashpoint above 200° F (93° C) is not regulated as a hazardous material and may be mailed subject to the general packaging requirements in DMM 601, provided it possesses no characteristics of another hazard class.” (Publication 52, 343.1)	The rule that applies depends on the flashpoint printed on the oil's own Safety Data Sheet, and Publication 52 makes the mailer responsible for identifying it (323.1). This page makes no claim about any oil's flashpoint. Above 200°F, and with no hazard of another class, pack it as a liquid (shipping liquids). At 200°F or below it is a combustible or flammable liquid, with per-package limits by flashpoint band and ground only at 140°F or below; at 20°F or below it is nonmailable (343.21, 343.22; the bands are on perfume, nail polish and aerosols). Flammable and combustible liquids can't go to other countries (343.21, 343.22).
Live plants and other plant products, within the US	Mailable with conditions	“Plants and plant products are mailable within the United States, its territories, and possessions, but are subject to certain prohibitions and restrictions imposed by federal agricultural and conservation statutes.” (Publication 52, 561; 562)	A plant, plant product or other article that can carry a dangerous plant disease or insect infestation is nonmailable from a quarantined area when USDA prohibits shipping it (562), and Hawaii, Puerto Rico and the U.S. Virgin Islands have quarantines of their own (562.1). For specifics, USPS points to its Publication 14 and to USDA's Animal and Plant Health Inspection Service (562.2, 564). Some states inspect plant mail on arrival: as Publication 14 explains, the Terminal Inspection Act makes it unlawful to mail a plant or plant product to a state or territory that inspects it unless the outside of the package fully and conspicuously identifies the contents (Publication 14, 21), and the lists of inspected plants are approved by USDA and available from APHIS (Publication 14, 22 and 27). Wrap roots and wet packing in waterproof material such as plastic wrap or waxed kraft paper, cover the tops, and use a puncture-proof wrapper for a plant with thorns (563). Plants are perishable matter (511), so the Live Animal and Perishable Handling Fee applies (513): $7.50 by Ground Advantage, $15.00 by Priority Mail (Notice 123).

Items with a page of their own

Matches and lighters: Book, box and strike-anywhere matches, and lighters with or without fuel. Matches and lighters
Perfume and cologne: Alcohol-based fragrance, with how much fits in one box. Perfume, nail polish and aerosols
Nail polish and polish remover: Polish, and why acetone remover is different. Perfume, nail polish and aerosols
Aerosol cans and spray paint: Flammable spray cans, by container type. Perfume, nail polish and aerosols
Paint, varnish, lacquer and latex paint: Liquid finishes are on the same page as nail polish (Publication 52, 343.23). Perfume, nail polish and aerosols
Liquids that aren't hazmat (shampoo, lotion, syrup): Caps, triple packaging, arrows and the liquid fee. Shipping liquids
Spare lithium batteries: Loose lithium-ion and lithium metal batteries, by ground. Spare lithium batteries
Used phones, laptops, cameras and game controllers: Pre-owned devices with a lithium battery inside. Used electronics with batteries
Anything to another country: Each country's own list of what it bars. Shipping to other countries
APO, FPO and DPO addresses: Military and diplomatic mail has its own limits. APO, FPO and DPO

What Adult Signature and the perishable fee add to a label

On a Ground Advantage label you make online, an air gun that needs Adult Signature adds $9.70 for it and a live plant adds $7.50 for perishable handling, on top of postage; a rifle box longer than 30 inches adds a length fee as well.

Ground Advantage commercial (online label) to Zone 5, with postage and fees from USPS Notice 123 effective Oct 4, 2026. Weights and box sizes are examples; each box is under 1 cubic foot, so no dimensional weight. The postage is USPS's temporary holiday price, which runs until 12 a.m. CT Jan 17, 2027 (USPS).
Example	Weight and box	Postage	Added by the rule	Total
Air pistol (concealable, any speed)	2 lb, 12 × 8 × 3 in.	$10.50	Adult Signature Required $9.70	$20.20
Air rifle at 400 fps or more	7 lb, 40 × 8 × 4 in.	$15.95	Adult Signature Required $9.70 + longest side over 30 in. $10.00	$35.65
Live plant	2 lb, 12 × 8 × 8 in.	$10.50	Live Animal and Perishable Handling Fee $7.50	$18.00

Rules that apply to every row

Ground-only items never fly, Alaska and Hawaii included

A package USPS limits to ground can't go by air to any address. Publication 52, 327.13: “Hazardous materials designated for surface transportation must not, under any circumstances, be transported by air, except as provided for certain exceptions listed in 327.12(g).” (327.13). Hazmat sent as Priority Mail or Priority Mail Express has to meet the air rules whatever route it takes (327.12), so a ground-only item can't go as either; it goes by a ground service such as Ground Advantage.

The exception 327.13 points to is for used, damaged or defective electronics with lithium batteries, to Alaska ZIP Codes with no ground service: “For those ZIP Codes that are air transportation only due to the absence of ground transportation, a multimodal-transportation solution may be used to transport used, damaged, or defective electronic devices containing or packed with lithium batteries.” (327.12(g)). Appendix F lists 187 such ZIP Codes, all in Alaska.

For every other ground-only item in this table, and for the ground-only items on the matches, perfume and aerosol pages, 327.13 allows no air leg to those ZIP Codes, and section 327 names no exception for Hawaii. Publication 52 counts ground and vessel as surface transport (327.13) without saying which addresses each reaches, so ask your Post Office how a ground-only package gets to a Hawaii address, or to an Alaska ZIP Code on the list, before you accept the sale. Lithium-ion batteries mailed from and to addresses within Alaska have a rule of their own: spare lithium batteries.

The 187 Alaska ZIP Codes on Appendix F's air-only list

99545, 99546, 99547, 99548, 99549, 99550, 99551, 99552, 99553, 99554, 99555, 99557, 99558, 99559, 99561, 99563, 99564, 99565, 99569, 99571, 99574, 99575, 99576, 99578, 99579, 99580, 99581, 99583, 99585, 99589, 99590, 99591, 99602, 99604, 99606, 99607, 99608, 99609, 99612, 99613, 99614, 99615, 99619, 99620, 99621, 99622, 99624, 99625, 99626, 99627, 99628, 99630, 99632, 99633, 99634, 99636, 99637, 99638, 99640, 99641, 99643, 99644, 99647, 99648, 99649, 99650, 99651, 99653, 99655, 99656, 99657, 99658, 99659, 99660, 99661, 99662, 99663, 99665, 99666, 99667, 99668, 99670, 99671, 99675, 99677, 99678, 99679, 99680, 99681, 99682, 99684, 99685, 99689, 99690, 99691, 99692, 99695, 99697, 99720, 99721, 99722, 99723, 99724, 99726, 99727, 99730, 99732, 99733, 99734, 99736, 99738, 99739, 99740, 99741, 99742, 99745, 99746, 99747, 99748, 99749, 99750, 99751, 99752, 99753, 99754, 99756, 99757, 99758, 99759, 99761, 99762, 99763, 99765, 99766, 99767, 99768, 99769, 99770, 99771, 99772, 99773, 99774, 99777, 99778, 99781, 99782, 99783, 99784, 99785, 99786, 99788, 99789, 99790, 99791, 99801, 99802, 99803, 99811, 99812, 99820, 99821, 99824, 99825, 99826, 99827, 99829, 99830, 99832, 99833, 99835, 99836, 99840, 99841, 99850, 99901, 99903, 99918, 99919, 99921, 99922, 99923, 99925, 99926, 99927, 99928, 99929, 99950

Hazmat to territories other than Puerto Rico follows the international rules

Hazmat to a U.S. territory or possession outside the US customs territory is treated like mail abroad. Publication 52 puts the 50 states, DC and Puerto Rico inside that territory and says “shipments to U.S. Possessions, Territories, and Freely Associated States must follow the guidelines in 622 for mailable dangerous goods.” (612). Section 622 allows only a few kinds of dangerous goods in that mail: biological substances, limited amounts of radioactive material, certain magnetized material and lithium batteries installed in the equipment they power (622.1). Dry ice, CFLs, nonspillable batteries and flammable liquids are not among them.

Say it's hazmat when you make the label

Publication 52 makes you, the mailer, responsible for knowing an item's flashpoint and other hazards and for flagging hazmat when the label is made, USPS's own online labels included (323.1). What that adds by service: hazmat fees. Getting it wrong has a cost of its own: “Anyone who mails, or causes to be mailed, a nonmailable or improperly packaged hazardous material may be subject to legal penalties (i.e., fines and/or imprisonment)” (323.1).

Not here, or not sure? Ask USPS

When the rows above don't settle an item, USPS will rule on it: give the Post Office a description of the item and how you'll pack it, with the product's Safety Data Sheet if it may be hazmat, and if that isn't enough to decide, ask USPS Product Classification or the PCSC (Publication 52, 215.2 and 215.3).

How this page was made

We read the August 2026 edition of Publication 52 on USPS's Postal Explorer, and the other USPS pages under Sources, on Oct 31, 2026 and saved a copy of each; the site's tests match every quote on this page against those copies word for word. Postage and fees come from the site's Notice 123 data, the same figures as on its rate and rule pages. USPS is the authority on its own rules: if this page and USPS disagree, USPS wins, and we'd like to hear about it on the corrections page.

Sources

Read on Oct 31, 2026 from each official page below.

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