How to return a can to service safely, and when to retire it.
A metal jerry can is built to be reused for years, but only if it is cleaned correctly and retired when it should be.
Stainless steel can be scrubbed, sterilised and stored wet without holding odour, which is why it suits water and food indefinitely. A steel fuel can is reusable for fuel, but do not repurpose a fuel can for water or food; residue and the interior coating make that unsafe. Match the reuse to what the can was built for.
An empty fuel can is not a safe fuel can. The vapour ignites, not the liquid, and a container that looks drained still holds a fuel-air mixture that one spark can set off. Never apply heat, an open flame, a grinder or steam to a used fuel can. Those are the exact tools that ignite residual vapour. If a fuel can needs work of that kind, retire it instead of repairing it.
The reason is the flammable range. Petrol vapour ignites between roughly 1.4 and 7.6 per cent by volume in air. A full can holds a headspace far too rich to burn, and a drained one holds a mixture sitting squarely inside the range, with the rest of the volume made up by air that walked in as the liquid walked out. So draining a can does not make it safe; it moves the headspace from too rich to exactly right. The physics is on storing fuel safely.
It also explains why the usual remedies make things worse. Rinsing with water leaves a wet surface with fuel still in the seams and now a lower vapour concentration, which moves an already rich can further into the range rather than out of it. Purging properly means displacing the atmosphere with an inert gas or filling the can with water to the brim, and neither is a workshop job on a 20-litre can worth a fraction of the risk.
A fuel can never becomes a water or food can. Hydrocarbons soak into the interior coating and into every seam and thread, and rinsing does not draw them back out. The taint stays, and the coating was never made for potable contact. No cleaning regime reverses absorption, which is why this is written as a rule rather than as a precaution. The common mistake is to rinse a fuel can with water and refuel it, or to hand an old fuel can over for drinking water. The rule runs one way only: a can that has held potable water can later hold fuel without any of this applying, so plan a mixed fleet to migrate cans downwards through duties and never back. Keep water and food in stainless built for the job, and see food-contact and water certification.
For a chemical can, triple-rinse and neutralise exactly as the safety data sheet directs, then confirm the next liquid is compatible with both the residue and the plastic before you refill.
A seal that has gone hard, flattened or cracked is a part to replace, not a reason to bin the can. Gaskets, spouts and caps wear out before the body does, and swapping them restores a tight closure on an otherwise sound can. Keep the right spares on hand and read caps, closures and gaskets.
One condition applies on a UN-marked can and it is easy to trip over. The closure was part of the tested design, so a replacement has to be the same specification rather than one that fits. Swapping a gasket compound or a cap pattern for whatever is on the shelf keeps the can watertight and takes it outside its approval, which matters the moment the can carries dangerous goods again. Order spares against the design, not against the thread.
Washing removes what is on the surface. The reason fuel-to-food is a one-way rule is that hydrocarbons do not stay on the surface: they absorb into polymer walls, into gasket elastomers and into any porous or damaged interior coating, and they migrate back out slowly for a long time afterwards.
That is why a can can rinse clear, dry completely, pass every visual check and still taint water weeks later. The smell test is genuinely useful here, and it is a one-way test: no smell does not prove clean, but any smell proves contaminated.
The same logic applies less dramatically between chemicals. A container that held a strongly scented agrochemical or a solvent carries residue in the same places, so the safe pattern is dedication by contents rather than cleaning between them. Mark the can for what it holds and keep it there.
Check the closure and gasket seal, the spout or tap, and the body for corrosion, dents and swelling. A weeping seam or a corroded seat is a reason to retire the can, not to refill it. Run the same short check every time:
UN-certified packaging has requirements for reuse and reconditioning, and a can that carries dangerous goods must still meet them after it goes back into service. A plastic can also has a service life that dates from its manufacture, not from its first fill. Track both, and do not stretch a can past either one.
The number is fixed and it is shorter than most operators expect. Under ADR 4.1.1.15, plastic drums and jerricans may be used to carry dangerous goods for five years from the date of manufacture, unless a shorter period is prescribed for the substance or a competent authority approves otherwise. Both the month and the year count, so it is not a calendar-year allowance, and the clock starts when the can was moulded rather than when you bought it or first filled it.
You read that date off the can itself. The UN marking carries the year of manufacture and, on plastic packagings, the month as well, so a can bought as new old stock may already have spent a year of its life on a shelf. That is worth checking on a first delivery from a new supplier: a discount on a can with eighteen months already gone is not a discount. Our UN packaging codes guide walks through the marking.
Steel and stainless carry no equivalent expiry, which is a real part of the case for metal on a dangerous-goods duty that repeats for years. What metal carries instead is a condition requirement, so the inspection below is what keeps it in service rather than a date.
The words get used loosely and they are defined terms with different consequences. A reused packaging is refilled as it stands, and the filler is responsible for satisfying themselves it still meets the design type. A reconditioned one has been cleaned to its original materials, had non-integral parts replaced and been restored to shape, and it carries an additional marking naming who did the work and when. A remanufactured one has been converted from one design type to another, and it re-enters service as a new packaging.
What matters commercially is that only the first is free. Reconditioning is a certified operation with its own marking and its own liability, so a supplier offering cheap “reconditioned” cans without that marking is offering used ones. On a dangerous-goods duty the filler carries the consequence, not the seller, which is why a returned container with no traceable history is worth less than nothing.
Reuse also brings a testing obligation that most operators skip. A packaging going back into dangerous-goods service must still be capable of passing the design-type tests, and the practical expression of that is periodic leakproofness testing on the closure and the body rather than a visual check. Build the test into the return loop or the loop is not compliant, however sound the cans look.
Retire a can with internal corrosion, a coating breached to bare rusting metal, a split or deep dent, or a closure that no longer seals. A plastic can also has a service life from its date of manufacture. Read HDPE grades on plastic service life. When you are unsure, retire it.
Retirement is a decision worth making at a fixed point rather than in the moment, because the moment always argues for one more fill. Inspect on receipt back from the field rather than at the next issue, mark a failed can immediately so it cannot re-enter stock, and physically destroy the closure on anything retired from dangerous-goods service. A can put aside to be dealt with later is a can somebody will use.
Reuse follows the material. Here is what earns a long service life.
| Your use case | Recommended can | Why this one |
|---|---|---|
| Water and food, reused for years |  20L Stainless Steel Water Can |
Stainless scrubs, sterilises and holds no odour. |
| Fuel, reused for fuel only |  20L NATO Steel Fuel Can |
Coated steel; never repurpose it for water. |
| Food and potable liquids |  Food-Grade HDPE Jerrycan |
Food-grade HDPE with documentation. |
| Replacing a worn seal |  Caps, Closures & Gaskets |
A gasket is a wear part, not a write-off. |
Drain fully, wash with warm water and a detergent suited to the previous contents, agitate, rinse repeatedly until the rinse water runs clear and odourless, then dry completely inverted. Any residual smell means residual contamination, and a can that will not lose the smell should be retired.
No. Hydrocarbons absorb into coatings, gaskets and plastic walls and continue to leach out after cleaning, and the interior was never certified for food contact. This is the single most common and most dangerous reuse mistake. Retire the can or keep it on fuel.
Any internal rust, any coating failure you can see or feel, a deformed neck or sealing face, a cracked or crazed plastic wall, or a UN-marked can past the service life its approval assumes. A can that no longer seals is not repairable in the field.
The standards and regulations this page relies on, at their issuing body. Where a market rule is named here, check the current revision before you specify against it.
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