Aerosol cans turn up in almost every Kiwi home — deodorant, hairspray, fly spray, spray paint, cooking oil, air freshener and more. Because they're made from steel or aluminium, both highly recyclable metals, it makes sense to keep them out of the red general-waste bin where possible. The catch is that aerosols are pressurised containers, and if they still hold propellant or product they can be a genuine hazard at recycling facilities, where they may explode or catch fire. Getting the basics right keeps workers safe and gives the metal a real second life.

The golden rule is simple: only recycle an aerosol can when it is completely empty. "Empty" means no liquid left and no hiss of propellant when you press the nozzle. Give it a final spray into the air or a rag until nothing comes out and the can feels light. Never try to puncture, crush, flatten or heat a can to empty it faster — that's exactly when accidents happen. Don't pierce them, and don't put them anywhere near heat, flames or the recycling truck's compactor while they still have pressure inside.

Once a can is genuinely empty, check whether your local council accepts aerosols in the yellow kerbside bin, as acceptance does vary around the country. Many councils take empty steel and aluminium aerosols, but some do not, so it pays to check your council's website or recycling guide. Where they're accepted, pop the can in loose and clean. Leave the can intact rather than crushing it, and don't bag your recycling. If aerosols aren't accepted at your kerbside, most transfer stations and community recycling centres will take them as scrap metal.

The plastic lid or cap is a separate issue. These small caps are usually too small to be sorted at recycling plants and are generally not recyclable through kerbside, so the simplest option is to remove the cap and put it in your general waste. The metal nozzle can stay attached to the can. A quick wipe to remove sticky residue from cooking-oil or paint sprays is helpful but you don't need to wash aerosols out with water.

The trickiest aerosols are those that aren't empty or that contained hazardous products. A half-used can of spray paint, insecticide, solvent-based product or anything labelled flammable or toxic should never go in any kerbside bin. Treat these as household hazardous waste and take them to a transfer station or a hazardous-waste collection day — many councils run these, and staff can tell you the right drop-off point. Spray paint cans in particular are often handled as hazardous waste because of both the propellant and the paint inside.

To sum it up in a practical way: use the can right down to empty, leave it intact, bin the plastic cap, and recycle the metal can only if your council accepts aerosols at kerbside — otherwise take it to a transfer station. Anything still full, part-full or marked hazardous goes to household hazardous waste, not the recycling bin. A few seconds of checking turns a potentially dangerous item into clean, valuable metal.