Smelly Proof Bags: What They Are, What They’re Good For, and Why the Sizes Matter
Quick Answer
Smelly Proof bags are reusable airtight storage bags made in California. Multi-layer nylon construction and a double-locking zip mean odour, moisture and air stay where you put them. We stock them in clear and black, five sizes (X Small to X Large), in packs of 5, 10 or 25. Prices start at £3.
Browse Smelly Proof bags at Willy Banjo →
There are a lot of smelly proof bags on the market. Most of them aren’t.
The seal goes after a few uses. The zip sticks or splits. The bag itself is thin enough that you can smell through it if you press your nose close enough. Fine if you’re storing paperclips. Not fine if you’re storing anything that actually has a smell.
Smelly Proof bags are different. They’ve been making them in California for over 20 years, and the design hasn’t changed much because it didn’t need to. Nylon-reinforced double-wall construction, a double-locking zip that actually locks, and a barrier that blocks odour, moisture and air getting in or out. They won the PTPA award in 2022 — Parent Tested Parent Approved — which tells you something about the range of people using them.
We stock them at Willy Banjo. Have done for years. Clear and black, five sizes, in packs of 5, 10 or 25.
How they actually block odour
The barrier is the bag itself. Multi-layer nylon construction means the material doesn’t let odour molecules through. Air doesn’t pass through. Smell doesn’t pass through. You could store the strongest-smelling thing you own and the outside of the bag gives nothing away.
The double-locking zip is the second part. A cheap zip-seal bag fails at the closure: the track wears, the seal misaligns, and you’ve got a bag leaking smell from the top even if the walls hold. Smelly Proof’s zipper is built to be opened and closed hundreds of times without losing the seal. That’s the difference between a bag you have to treat carefully and one you can use every day.
What they’re for
People use Smelly Proof bags for food first. Cheese that’d stink the fridge out. Snacks for a long drive. Spices loose in a rucksack. For camping they’re practical — no one wants their tent smelling of last night’s dinner or their sleeping bag full of moisture.
For travel they solve what suitcases and day bags don’t: containing liquids and powders that airport security won’t love if they leak, and keeping anything with a smell from becoming everyone else’s problem.
At festivals — and we’ve done a few — they’re essential for keeping kit together. Tobacco, rolling papers, pipe gear, anything that needs to stay dry and accessible without advertising itself. The black ones are worth knowing about if you’d rather people couldn’t see what’s in the bag at a glance.
General storage works too. Herbs, spices, medicine, anything with a smell or that needs to stay dry. They’re not single-use — wash, dry, reuse.
Clear or black
Clear lets you see what’s in the bag without opening it. Useful if you’re organised and want to find things quickly. Works well for food and camping kit.
Black keeps the contents private. Can’t see through them at all. Better if you’re carrying something you’d rather not have on display.
Both use the same construction. Same barrier, same zip, same seal. The difference is purely visual.
The sizes — and why most listings get them wrong
This is where it gets annoying if you’re shopping online. Most UK retailers list Smelly Proof bag dimensions that are wrong, approximate, or copied from somewhere else and never checked. The US brand website uses American naming — gallon, quart, snack — which doesn’t translate directly.
Here are the actual dimensions. External is the full bag size. Internal is the usable space inside.
| Size | External | Internal |
|---|---|---|
| X Small | 12.5 × 11.0 cm | 10.5 × 7.5 cm |
| Small | 17.0 × 14.5 cm | 15.0 × 9.5 cm |
| Medium | 17.5 × 23.5 cm | 15.5 × 18.5 cm |
| Large | 23.5 × 29.5 cm | 21.5 × 24.0 cm |
| X Large | 30.5 × 44.0 cm | 28.5 × 38.5 cm |
These apply to both clear and black.
X Small fits a lighter and a few papers. Small is a full rolling kit. Medium is what most people carry day-to-day — grinder, papers, tobacco, a pipe. Large is festival kit or longer-term storage. X Large is serious bulk storage.
Looking after them
Wash with soap and water and let them air dry. If you’ve stored something with a strong smell, baking soda in the wash helps neutralise it. Don’t put them on a radiator — air dry is fine.
The zipper track can collect residue with repeated use. A damp cloth along the teeth keeps it running clean. Don’t force the zip if it feels stiff — something’s caught in the track.
Temperature-safe from -19°C to 88°C. Works for food storage including sous vide if you’re that way inclined.
Made in the USA. BPA free.
The material is FDA approved. No BPA, no phthalates. Worth knowing if you’re storing food or anything going near your mouth.
Smelly Proof bags are reusable. Wash them out and they come back fine. At the price per bag — especially in the 25-pack — they work out cheap for what they do. The brand’s been making them since the early 2000s. smellyproof.com has the full story if you want it.
Smelly Proof bags — FAQ
Are Smelly Proof bags actually smell-proof?
Yes, as long as the seal is closed properly. The multi-layer nylon wall stops odour passing through the material. The double-lock zip keeps the closure airtight. If you can smell anything, check the zip is closed fully across the whole width — it needs to be tracked right to both ends.
Which size should I get?
X Small for a lighter and a few papers. Small for a full rolling kit. Medium for daily carry — grinder, tobacco, pipe, papers all fit. Large for festival kit or if you’re storing rather than carrying. X Large is for bulk. When in doubt, one size up.
How long do they last?
The zipper is rated for hundreds of opens and closes. The nylon material doesn’t degrade with washing. With normal use they’ll last years. At 25-pack prices, the cost per use is low enough that it’s not worth worrying about.
Can I use them for food?
Yes. FDA-approved material, BPA-free, no phthalates. Safe from -19°C to 88°C, which covers most food storage including sous vide. Wash between uses with soap and water.
Can I wash them?
Soap and water, air dry. Baking soda helps if the smell lingers. The zipper and material both handle repeated washing. Dishwasher works if you don’t mind losing the printed branding.
What’s the difference between these and a regular grip-seal bag?
A standard grip-seal bag is single-layer polyethylene. Odour passes through the material over time and the seal isn’t truly airtight. Smelly Proof uses multi-layer nylon construction — a different material doing a different job. The zipper is built for hundreds of uses rather than a handful before it splits. That’s where the extra cost goes.
Get Smelly Proof bags at Willy Banjo
We stock the full range. Clear and black, X Small through X Large, in 5, 10 and 25 packs. Prices start at £3.
13a Lowthian Street, Preston. Or online — we post out every day.