Two related problems get lumped together under “plastic smell”: a brand-new bag or container that off-gasses an unpleasant plastic odour into your fridge or cupboard, and the opposite problem, a strong-smelling product that needs to stay contained inside a bag so it does not smell up a car, a cupboard, a warehouse or a parcel. Both come down to the same underlying science, how easily odour molecules move through a material, so this guide covers both: how to get plastic smell out of a new bag, and how genuine odour-barrier bags actually stop smell getting out (or in) in the first place.
Why new plastic smells
New plastic packaging often carries a noticeable smell because the manufacturing process leaves trace volatile organic compounds (VOCs), residual solvents, plasticisers and processing aids in the material. These compounds are volatile by definition, which means they evaporate off the surface over time, and that is what you are smelling. It is most noticeable in:
- Vacuum-sealed bags, where the film has been freshly extruded and heat-sealed.
- Reusable plastic storage bags, particularly thicker or coloured formats.
- Bags marketed as “smell proof,” ironically, because the barrier layers that stop odour escaping are themselves often the source of the initial new-plastic smell.
- Food-grade containers moulded from certain resins.
At normal household exposure levels this odour is not a safety concern, but it is unpleasant and can taint food, especially anything porous or high in fat that readily picks up airborne compounds.
How to remove plastic smell from a bag
| Method | How | Best for |
|---|---|---|
| Air it out | Open the bag fully in a well-ventilated area for 24 to 48 hours. | Almost everything; do this first regardless of what else you try. |
| Wash | Mild dish soap and warm water, rinse thoroughly, dry completely. | Bags and containers that will hold food. |
| Baking soda | A spoonful sealed inside the bag for 24 hours, then shaken out or rinsed. | Persistent odour after washing. |
| Diluted vinegar | Equal parts water and white vinegar, wipe or soak 15 to 30 minutes, rinse and air dry. | Stronger chemical-type odours. |
| Activated carbon | A small sachet or piece sealed inside for a day or two. | Odour that lingers after washing and airing. |
| Citrus peel or coffee grounds | Sealed inside for 24 hours. | A milder, more pleasant masking effect alongside the methods above. |
To avoid the problem: wash new bags before first use, store new stock in ventilated conditions rather than sealed in its own packaging, and avoid putting hot or strongly scented food straight into a thin, freshly made bag.
The other direction: what actually makes a bag “smell proof”
If your problem is the reverse, keeping a strong-smelling product from being detected through the bag, baking soda and airing will not help. That is a materials-science problem, not a cleaning problem, and it is worth understanding the real terms rather than the marketing language.
Smell is a gas problem, not a fabric problem
What you smell is airborne odour molecules (volatile organic compounds) that have passed through the packaging material. A single layer of standard polyethylene is porous to gases at a molecular level. Odour molecules, along with oxygen and water vapour, migrate through it over time. A bag only becomes genuinely odour-proof when it uses a material, or combination of materials, that gas molecules cannot easily pass through.
Multi-layer barrier laminates
Genuine smell-proof bags are built from a laminate, several thin layers bonded together, each doing a different job:
- An outer structural layer, often PET, for strength and printability.
- A barrier layer: aluminium foil, a metallised film (often loosely called “mylar,” which is really metallised BoPET), or a barrier resin such as EVOH (ethylene vinyl alcohol). This is the layer that actually stops gas transmission, foil and metallised layers are close to impermeable; EVOH is one of the best barrier plastics available.
- A puncture and durability layer, commonly nylon (polyamide), used in the multi-layer poly/nylon laminates common in reusable bags.
- An inner heat-seal layer, usually LLDPE or PE, which is what actually gets fused to form the bag’s seams.
This is why a single-layer poly bag, however thick, is not a substitute for a proper barrier laminate: thickness alone slows gas transmission, it does not stop it the way a foil or EVOH layer does.
Activated carbon: adsorption, not just a barrier
Some smell-proof bags add an activated carbon (activated charcoal) lining. Carbon works differently from a barrier film: instead of blocking molecules from passing through the material, its extremely porous surface physically adsorbs odour molecules that reach it, capturing them rather than letting them pass or simply masking them. Carbon-lined bags are common where the contents are especially aromatic, since the lining actively soaks up compounds that a barrier film alone might still let trace amounts of through over a long period.
Heat-sealed seams, not a “coating”
The seams are usually the weak point of any bag, so how they are formed matters as much as the film itself. Proper odour-barrier bags use heat sealing: the inner PE or LLDPE layer on each side of the seam is heated and pressed together until it fuses into a continuous, gas-tight bond. This is sometimes loosely described as a thermal process because heat and pressure are what create the seal, but it is lamination and heat-sealing, not a separate “coating” applied afterward. A bag with an excellent barrier film and a poorly formed or hand-folded seam will still leak odour at the seam, which is why closure design (heat-sealed seam, double zip-lock, roll-top, or a combination) is engineered alongside the film itself.
How barrier performance is actually measured
The packaging industry does not generally test for a single “odour transmission rate” the way it tests other properties. Instead, barrier films are rated on:
- Oxygen Transmission Rate (OTR), tested to methods such as ASTM D3985, measured in cc/m²/24hr.
- Water Vapour Transmission Rate (WVTR/MVTR), tested to methods such as ASTM E96 or ASTM F1249, measured in g/m²/24hr.
Most odour molecules are similar in size to, or larger than, oxygen and water vapour molecules, so a film engineered for a low OTR and WVTR is, in practice, also an effective odour barrier. Where a specific claim about odour containment matters, that is usually confirmed with sensory (panel or “sniff”) testing on the finished, filled and sealed bag, rather than a single lab number, because real-world performance depends on the film, the seal, and how the bag is filled and closed together.
Does vacuum sealing make a bag smell proof?
No, not by itself. Vacuum sealing removes the air from inside the bag, which reduces the volume of gas available to carry odour and slows the initial release, but it does not change how permeable the film itself is. Over time, odour molecules will still migrate through a standard vacuum bag film at whatever rate that film allows. A genuinely odour-proof result needs a barrier film (foil, metallised, or EVOH-based), not vacuum alone.
Reusable vs single-use smell-proof bags
| Single-use barrier pouch | Reusable smell-proof bag | |
|---|---|---|
| Typical construction | Thinner foil or metallised laminate, heat-sealed once | Heavier-gauge laminate or fabric-backed exterior with a laminated liner |
| Closure | Factory heat-seal, cut open to use | Reinforced zip-lock, double zip, or roll-top designed for repeated opening and closing |
| Reuse | Not designed to reseal to original performance once cut | Designed to be wiped clean and resealed many times |
| Best for | High-volume single-fill packaging | Ongoing storage, transport, or repeated handling of the same odour-generating product |
Choosing the right bag for the problem you actually have
- Identify the odour and moisture profile of the product. Oily, high-VOC or high-moisture products need a stronger barrier and, often, a carbon lining.
- Match the closure to how it will be used. A one-time shipment can use a heat-sealed pouch; a bag opened and closed repeatedly needs a reinforced zip or roll-top rated for repeated use.
- Size it to the product, with minimal excess air space, since a bag mostly full of trapped air gives odour more room to accumulate before it needs to escape.
- Check for food-grade or compliance requirements if the bag will hold food, and for tamper-evidence if that matters for your product.
- Decide single-use or reusable based on volume and how many times the same bag needs to be opened.
How Carewell Group helps
Carewell Group is an Australian packaging manufacturer and supplier, certified to ISO 9001, ISO 14001 and ISO 45001. Rather than selling one generic smell-proof bag to every customer, Carewell engineers the bag around the product:
- Barrier and lining selection, matching activated carbon, foil or metallised film, or multi-layer poly/nylon laminates to your product’s specific odour and moisture profile.
- Layer and thickness engineering, specifying layer count and gauge to what the product actually needs through transport and storage, not a generic one-size number.
- Closure and seal design, heat-sealed seams, double-zip locks, roll-tops or tamper-evident features depending on the application.
- Custom sizing and branding, from small sample pouches to bulk industrial formats.
- Real-world testing, validating the finished bag under actual handling and transport conditions, not just to a paper spec.
See the full detail on custom-engineered odour control bags. This work commonly supports food manufacturers and meal-prep services (see food fulfilment packaging), pet product and waste-management businesses (see pet food packaging), and logistics operations needing consistent odour control at scale. Standard poly bags and mailers are also available in the poly bags and mailers range.
Carewell can meet all your packaging needs for your business. Talk to our expert and we will work to your required MOQ. Call +61 (02) 8760 1491 or request samples and a specification review.
Frequently asked questions
Why does my new plastic bag smell?
New plastic releases trace volatile organic compounds left over from manufacturing. It is not usually a safety concern, but airing, washing, baking soda or activated carbon will remove it.
What actually makes a bag smell proof?
A multi-layer barrier laminate, typically foil, metallised film or an EVOH barrier resin, combined with a properly heat-sealed or reinforced closure. Thickness alone does not make a bag odour-proof; the barrier material and the seal quality do.
Are vacuum-sealed bags smell proof?
Not by themselves. Vacuum sealing reduces trapped air but does not change how permeable the film is. A true odour-proof result needs a barrier film, not vacuum alone.
What does activated carbon do in a smell-proof bag?
It adsorbs odour molecules onto its porous surface rather than just blocking them, which is why carbon-lined bags are used for particularly strong-smelling products.
Is there an “odour transmission rate” standard like there is for oxygen?
Not a single universal one. Barrier films are rated on Oxygen Transmission Rate (ASTM D3985) and Water Vapour Transmission Rate (ASTM E96 / ASTM F1249), and odour performance is generally confirmed with sensory testing on the finished, sealed bag.
Can a smell-proof bag be reused?
Yes, if it is built for it: a heavier-gauge laminate or fabric-backed bag with a reinforced zip-lock or roll-top closure, rather than a single-use heat-sealed pouch.
Sources
- ASTM D3985, oxygen gas transmission rate through plastic film: astm.org
- ASTM E96 / ASTM F1249, water vapour transmission rate of materials: astm.org
Written by Alif Vasaya, digital and content strategy, Carewell Group. Carewell Group is an Australian packaging, food packaging, tape, industrial safety and 3PL supplier serving all of Australia. Last updated 14 September 2026.