What You Can't Ship With USPS, FedEx, or UPS — And What to Do Instead

Every carrier has a list of items they won't touch — or will only accept under strict conditions. Shipping the wrong thing the wrong way can result in refused packages, fines, or confiscated shipments. Here's the complete guide for Monroe-area shippers.

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Most people assume that if it fits in a box, it can be shipped. That assumption causes real problems — packages intercepted mid-transit, orders refunded, customers left waiting, and in some cases, federal fines. Whether you're a Monroe resident shipping a gift, a small business sending product, or an Etsy or eBay seller clearing inventory, knowing what each carrier will and won't accept can save you a lot of grief.

This guide covers the most common restricted and prohibited items across USPS, FedEx, and UPS, explains the key differences between the carriers, and tells you what to do when you're not sure.

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Why Carrier Rules Differ — and Why It Matters

USPS is a federal government agency. That means its rules are set by federal law (the Mailable Matter regulations in Title 18 of the U.S. Code), not corporate policy. Violations of USPS shipping rules can carry criminal penalties.

FedEx and UPS are private carriers. Their prohibited-items lists are shaped by insurance liability, carrier safety policies, international treaty obligations (for cross-border shipments), and DOT/IATA hazardous materials regulations. They also have more flexibility — some items USPS won't accept, FedEx or UPS will, under the right conditions.

The short version: you need to know which carrier you're using before you pack, not after.

The Mail Station Monroe is an authorized FedEx shipping location and handles USPS, UPS, and DHL. Our staff fields questions about restricted items regularly — this guide reflects what we see most often from Monroe, Sultan, Gold Bar, and Snohomish County shippers.

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Flat-Out Prohibited: Items No Carrier Will Ship

Some items are prohibited by every major carrier, often because federal law requires it:

• Explosives (fireworks, blasting caps, gunpowder)
• Illegal drugs and controlled substances without proper authorization
• Human remains (via standard parcel services — specialized freight is different)
• Hazardous waste and radioactive materials above trace thresholds
• Counterfeit goods or intellectual property violations
• Live animals (with narrow exceptions for specific species via USPS only)
• Items that violate import/export laws at the origin or destination

These aren't gray areas. If your package contains any of the above, no carrier at The Mail Station Monroe — or anywhere else — will ship it.

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The Items That Cause the Most Trouble: Category by Category

Lithium Batteries

This is the single most common source of confusion for Monroe shippers, especially those selling electronics, tools, or hobby equipment.

Lithium batteries power everything from laptops to electric toothbrushes to cordless drills, and their shipping rules are some of the most complex in the industry.

The key rule: batteries installed in a device are treated differently from loose/spare batteries. Shipping a laptop with its battery is generally fine. Shipping a box of loose replacement laptop batteries requires compliance with UN 38.3 testing documentation, watt-hour limits, quantity limits per package, and specific packaging requirements.

For Monroe sellers shipping electronics with lithium batteries, the safest approach is to bring your items to The Mail Station Monroe where staff can help classify your shipment correctly before it leaves.

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Alcohol and Wine

Shipping wine or spirits is one of the most misunderstood areas of carrier policy — because the rules exist at the state level, not just the carrier level.

• USPS: Categorically prohibits shipping any alcohol, domestically or internationally. No exceptions.
• FedEx: Allows alcohol shipments but only between licensed shippers and licensed retailers. Private individuals cannot use FedEx to ship alcohol.
• UPS: Same as FedEx — licensed entities only, with state-level compliance required on both ends.

Washington State allows direct-to-consumer wine shipments from licensed wineries to Washington residents — but that license must exist on the shipper's side. If you're a Monroe resident trying to ship a bottle of wine as a gift to someone in Oregon or California, you cannot do it through any standard carrier without a shipping license.

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Firearms and Ammunition

Firearms can be shipped legally under specific conditions, but the rules are strict and vary by state.

Washington State has its own firearms transfer requirements. If you're shipping a firearm in or out of Monroe, involving a licensed FFL dealer is almost always required. Attempting to ship a handgun via USPS without FFL involvement is a federal crime.

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Perfume, Cologne, and Aerosols

Perfume and cologne are flammable liquids. Most contain alcohol concentrations that trigger hazmat classifications when shipped in quantity.

• USPS: Permits small quantities of flammable perfume/cologne via ground transport only. Air services (Priority Mail Express) are prohibited for most flammable liquids.
• FedEx: Permits with proper ORM-D or Limited Quantity labeling. Air shipment has stricter limits.
• UPS: Similar to FedEx — allowed with proper classification and packaging.

For individual gift packages with a single bottle of perfume, USPS ground service is usually fine domestically. The problems arise when Monroe sellers ship multiple bottles at once — at a certain quantity, you're in hazmat territory and need specific labeling.

Aerosol cans follow similar rules: allowed in limited quantities via ground, tightly restricted or prohibited via air.

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Dry Ice

Dry ice is used to ship perishable food, medical samples, and some biological materials. It's a hazardous material (Class 9) because it releases CO₂ gas.

For Monroe residents shipping homemade food products, perishable gifts, or small business food orders: dry ice shipments require the package to be clearly marked, not airtight (to allow CO₂ to escape), and within carrier weight limits. Air shipments have additional restrictions.

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Perishables and Food

Unprocessed meat, seafood, dairy, and other perishables can be shipped — but only with appropriate packaging to prevent spoilage or leakage. If a package leaks, the carrier can refuse it, and you're liable for any damage to other packages.

Carriers require that perishable items be packaged so they can survive the maximum transit time plus 24 hours. For anything that needs refrigeration, this almost always means insulated packaging plus dry ice or gel packs. An improperly packaged perishable shipped from Monroe that leaks in transit can result in the entire shipment being discarded.

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Marijuana and Cannabis Products

Washington State legalized recreational marijuana, which creates a persistent point of confusion.

Federal law still classifies marijuana as a Schedule I controlled substance. USPS, as a federal agency, absolutely cannot ship cannabis products — period. FedEx and UPS, while private carriers, also prohibit marijuana shipments because the interstate transport of cannabis violates federal law regardless of state law at either end.

CBD products derived from hemp (under 0.3% THC) occupy a grayer area — but carriers still require compliance documentation and many refuse them entirely. If you're a Monroe business in the CBD space, talk to your carrier before shipping.

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Prescription Drugs

Shipping prescription medications is legal in limited circumstances — primarily between licensed pharmacies, healthcare providers, or directly to patients under a valid prescription. Private individuals mailing prescription drugs to friends or family is illegal, regardless of whether the medication is for a legitimate medical purpose.

Over-the-counter medications can generally be shipped without restriction.

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International Shipping: The Rules Get Harder

Every item above has additional complexity when crossing a border. Washington State's location as a Pacific gateway means Monroe businesses frequently ship to Canada, Mexico, Japan, South Korea, the Philippines, and beyond. The Mail Station Monroe handles international shipments with FedEx and DHL — and each destination country has its own import restrictions.

Common international problem areas:

• Food items: Many countries restrict or ban imported food, even packaged goods
• Supplements and vitamins: Some countries require import licenses
• Electronics: Certain components are restricted in some markets
• Leather goods: Require documentation in some countries about animal-product origin
• Seeds and plants: Heavily regulated at almost every international border

Before shipping internationally from Monroe, check the destination country's customs restrictions. Our staff can help identify obvious red flags before your package leaves.

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A Practical Comparison: What Each Carrier Handles Best

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What Happens If You Ship Something You Shouldn't?

The consequences range from minor to serious:

• Package refused or returned: Discovered at the counter before shipment
• Package intercepted in transit: Opened, inspected, refused delivery
• Package confiscated: For prohibited items, especially with federal implications
• Carrier fine: Private carriers can charge fees for improperly declared hazmat
• Federal charges: For USPS violations involving prohibited items or illegal drugs/firearms
• Civil liability: If a misdeclared package causes damage to other shipments or people

The smart move is always to ask before you ship — not after your package is sitting in a facility somewhere in Memphis with a hazmat flag on it.

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The Mail Station Monroe: Ship It Right the First Time

The Mail Station Monroe has been helping Monroe, Sultan, Gold Bar, Duvall, and Snohomish County residents ship correctly since 1982. Our staff is familiar with carrier rules for common restricted items and can help you:

• Identify whether your item requires special labeling or packaging
• Choose the right carrier for your item and destination
• Ensure your package meets dimensional and weight requirements
• Ship internationally with the right customs documentation

We're an authorized FedEx Authorized ShipCenter and handle USPS and DHL services as well. If you're not sure whether what you're shipping is allowed — or which carrier to use — come in before you pack. It's much easier to solve the problem at 19916 Old Owen Road than to track down a package that's been flagged in a carrier facility two states away.

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Get Help Before You Ship

The Mail Station Monroe

📍 19916 Old Owen Road, Monroe, WA 98272
📞 (360) 805-9250
🕐 Mon–Fri 9 AM–6 PM · Sat 9 AM–4 PM · 24/7 mailbox access
✉️ First month free for new mailbox customers

Walk in with your item and our staff will help you figure out the right carrier, the right packaging, and the right paperwork. No guesswork, no surprises.

Explore our shipping services →

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Related Reading

FedEx vs. UPS: Which Carrier Should You Use in Monroe, WA? — A detailed breakdown of service levels, pricing factors, and which carrier wins for different package types from Monroe.

The Complete Shipping Guide for Monroe, WA (2026) — Everything a Monroe resident or business needs to know about shipping domestically and internationally from Snohomish County.

FedEx Shipping Options in Monroe, WA: A Complete Guide — Every FedEx service level explained, from overnight express to economy ground, for Monroe-area shippers.

How to Ship to Canada from Monroe, WA — Customs forms, duties, carrier options, and what Canadian customs will and won't accept from Washington State.

International Shipping Customs Forms: A Guide for Monroe, WA Shippers — What CN22, CN23, and commercial invoices actually require, and how to fill them out correctly.

How to Return Amazon, FedEx, and UPS Packages from Monroe — The fastest, least frustrating way to process returns at The Mail Station Monroe using QR codes and prepaid labels.

Shipping Insurance and Carrier Liability: What Monroe Shippers Need to Know — What carriers actually cover when a package is lost or damaged — and when you need third-party insurance.

Oversized and Heavy Package Shipping in Monroe, WA — Dimensional weight pricing, large-package surcharges, and how to ship bulky items without overpaying.

UPS & FedEx Residential Surcharges Just Got More Expensive — The 2026 rate increases explained, and why a commercial receiving address in Monroe saves Monroe businesses money.

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Explore Services

• FedEx Shipping — Authorized FedEx ShipCenter in Monroe. Drop off, ship out, and get carrier guidance for any package type.
• International Shipping — FedEx and DHL international services from Monroe, with customs documentation support.
• Package Receiving — Receive packages at a secure commercial address in Monroe. All carriers accepted, held until you're ready.
• Mailbox Rentals — A real Monroe street address for your mail, packages, and business correspondence.

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The Mail Station Monroe — serving Monroe, Sultan, Gold Bar, Snohomish, Duvall, and the Highway 2 corridor since 1982. 19916 Old Owen Road, Monroe, WA 98272.