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.
Quick answer: How do you clean a jerry can?
Cleaning follows the last contents. Wash a stainless water can with hot water and food-safe detergent, rinse and sterilise it. Drain a steel fuel can fully, keep water out of it and never heat or grind it. Decontaminate a chemical can as its safety data sheet directs. A fuel can never becomes a water or food can.
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.
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 or a grinder to a used fuel can. Those are the exact tools that ignite residual vapour, and steam cleaning is a specialist job. 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. A drained one holds a mixture inside the range, with the rest of the volume made up by air that came in as the liquid went out. Draining a can does not make it safe. It moves the headspace from too rich to burn into the flammable range. 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, so this is a rule. 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. 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. Hydrocarbons do not stay on the surface, which is why fuel-to-food is a one-way rule. They absorb into polymer walls, into gasket elastomers and into any porous or damaged interior coating, and they migrate back out 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 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.
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. Check it 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 after an examination finds no defect that would affect the performance tests, and the filler is responsible for satisfying themselves it still meets the design type. A reconditioned one, which ADR defines in particular for metal drums and plastic drums and jerricans, has been cleaned to its original materials, had non-integral gaskets replaced and been inspected. It carries an additional marking naming who did the work and when. A remanufactured drum has been converted to another UN type or rebuilt with new structural parts, and it re-enters service as a new packaging.
Only reuse 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. Under ADR that means an inspection before each fill and a leakproofness test after reconditioning, and US rules require a leakproofness retest before each reuse. Build the right check into the return loop, 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.
Make the retirement decision at a fixed point rather than in the moment, because in the moment you will want 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.
Yes, wherever water reaches bare steel. A coated steel fuel can keeps its contents off the metal with an interior lining, and ADR 2025, 6.1.4.4.4, requires such a coating wherever the steel does not suit the contents. Rust inside means that lining has failed somewhere. The Canadian Conservation Institute ranks the conditions: rusting is slow in clean dry air, faster in humid air and faster still under a thin film of water (CCI Notes 9/6).
Water reaches the steel in four ways:
Stainless steel has no lining to lose and HDPE does not rust (steel vs HDPE fuel cans). Most NATO pattern cans are lined cold-rolled steel, so a failed lining is how they rust through.
Rust can come out of a steel can, but on a can that has held petrol the vapour comes first. For a working fleet our advice stands as above: retire a can with internal corrosion. Tanks and drums that seem empty usually still hold residue in the bottom, seams and crevices, and a teaspoon of petrol in a drum can be enough to cause an explosion when heated and turned into vapour (HSE INDG314). Blowing air through is rarely enough on its own, because a gas detector may miss residue in the seams. Empty and drain the can, ventilate it away from ignition sources (venting and pressure explains the vapour space), and keep heat, flame, grinders and electric current away from it.
Three methods are common, and each brings something into the can:
The acids and electrolysis leave the can wet, and bare steel rusts again once wet. CCI warns that iron cleaned back to bare metal can re-corrode in orange spots, and ISO 8501-4 grades the flash rust that forms on steel cleaned by water jetting. Rinse, drain and dry the can at once: cap off, inverted, in moving air at room temperature, never with a heat gun or flame. Inspect it with a light designed for flammable atmospheres, which HSE asks for inside any tank.
Removal cannot restore what the rust consumed. The steel it ate stays lost, and ADR defines a design type by its design, size, material and thickness, manner of construction and packing (6.1.5.1.2). The lining stays gone wherever rust formed. Before a UN-marked can carries dangerous goods again it must be free from corrosion and capable of passing the design-type tests recorded on its test report. A packaging showing reduced strength against its approved design type shall no longer be used unless reconditioned to withstand those tests (ADR 2025, 4.1.1.9). ADR’s definition of reconditioning names metal drums and plastic drums and jerricans, and describes no process for a steel jerrican.
ADR’s drum standard makes a fair yardstick, rejecting visible pitting, significant loss of material thickness, metal fatigue and damaged threads or closures (1.2.1). Retire the can after treatment if you find:
A steel can lasts as long as its lining, seams and closure stay sound, and no rule gives it a life in years. ADR sets a period of use for plastic drums and jerricans only (4.1.1.15, above), and we found no standard that gives steel a figure. Gaskets wear out first and are spare parts; the body ends with rust at the base, a seam or the closure seat. On our NATO steel fuel can we ask fuel users to check the coating and gasket at intervals.
A plastic can has a second clock: sunlight. HSE notes that plastic containers in particular can degrade with prolonged exposure to sunlight (HSG51, paragraph 70). ADR 6.1.4.8.2 asks that any UV protection come from carbon black or other pigments or inhibitors that stay effective throughout the life of the packaging. Retire a plastic can whose wall has crazed or split, whatever its date. The UN mark carries the year and a plastic can also carries the month, as the UN 3H1 guide shows, and HDPE properties covers heat and UV.
Storage sets the pace for both. Keep a can upright with the cap closed, somewhere cool, shaded and ventilated, as how to use a jerry can sets out; the Boat Safety Scheme also tells boaters to stow petrol cans securely upright. On its side a standard can rests its contents on the closure and keeps the gasket under load. The US emission rule requires portable fuel containers designed free of leaks upright, partially inverted or completely inverted (40 CFR 59.611(c)(2)), a test of a new can that says nothing about storing an aged one. Horizontal cans are built to lie flat, so store each can the way it was designed to stand (storing fuel safely). Keep steel off wet ground: HSG51 asks that rainwater not collect in a store, to guard against corrosion of metal containers on the ground (paragraph 149).
Reuse follows the material. These cans earn 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 a common reuse mistake and a dangerous one. Retire the can or keep it on fuel.
Retire it for any internal rust, any coating failure you can see or feel, a deformed neck or sealing face, or a cracked or crazed plastic wall. Retire a plastic UN jerrican on dangerous-goods duty five years after manufacture (ADR 2025, 4.1.1.15). A hardened or cracked gasket is a spare part. A closure that still weeps with a new gasket fitted means the neck or seat is damaged, and that is not repairable in the field.
A resin sealer can close cracks and holes, and HSE lists epoxy resins as a cold repair for tanks, but we do not suggest one for a UN-marked jerry can. The sealer adds a material the tested design did not include. ADR defines a design type by its design, size, material and thickness, and repeats the tests after each change of design, material or construction (ADR 2025, 6.1.5.1.2 and 6.1.5.1.4). A can that leaks through its wall is due for retirement anyway.
Not to carry dangerous goods under ADR, unless the competent authority approves otherwise: plastic drums and jerricans have a period of use of five years from manufacture (ADR 2025, 4.1.1.15). Carriage by private individuals of fuel for their own use sits outside ADR, within 60 litres per receptacle and 240 litres per transport unit and provided the can does not leak (1.1.3.1(a)). National container rules still apply, and sunlight still ages the wall, so retire the can once it crazes or splits.
Not by a date, except a plastic can carrying dangerous goods, which ADR limits to five years from manufacture. A steel can has no expiry. The US emission rule sets a useful life of five years from sale to the ultimate purchaser, the period over which a portable fuel container must keep meeting its emission standard (40 CFR 59.611(d)). That is a compliance period for the maker and puts no use-by date on the owner. Retire any can that leaks, pits, crazes or no longer seals.
Yes. The US Consumer Product Safety Commission says never to leave fuel containers open and to put the cap back on after use. An open can lets vapour out into the store and lets rain and moist air in, which the US EPA names as routes for water into a fuel system. Water can still condense inside a closed can when the temperature drops, so keep it upright in a cool, dry, ventilated place, off wet ground.
On a can carrying dangerous goods it does: ADR asks for every packaging to be inspected before filling to make sure it is free from corrosion (ADR 2025, 4.1.1.9). Off that duty, light rust on a flat panel is a paint repair, and HSE names painting as a way to protect stored containers against corrosion (HSG51, paragraph 88). Rust at a seam, the base or around the closure is a reason to retire the can.
Only when the leak is at the closure and the old gasket is the cause. A gasket that has gone hard, flat or cracked is a spare part. A weep from a seam, through the wall, or from a damaged thread or gasket seat is a body failure, and ADR’s reconditioning standard for metal drums rejects packagings with damaged threads or closures (ADR 2025, 1.2.1). On a UN-marked can, fit seals made to the original specification.
Wash it with hot water and a food-safe detergent, then rinse. To sanitise, the US CDC advises mixing 1 teaspoon of unscented household bleach, 5 to 9 per cent sodium hypochlorite, into 1 quart (about a litre) of water, shaking it in the closed container, waiting at least 30 seconds, pouring it out and letting the container air-dry. On a stainless can, rinse the solution out with clean water, because stronger hypochlorite attacks 304.
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.
Last reviewed by David Guru, Co-Founder & Business Development Director.
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