That collection of half-empty paint tins in the garage, the old bottle of turps under the sink, and the weed killer that's been lurking in the shed all have one thing in common: they're household hazardous waste, and they need special handling. Tipping them into your red general-waste bin, pouring them down the drain, or emptying them onto the garden can contaminate waterways, harm soil life, and put waste workers at risk. Paint solvents and garden chemicals are exactly the kind of thing that shouldn't end up in landfill leachate or the stormwater system that flows to our streams and harbours.

Paint is the easiest to deal with thanks to a nationwide product stewardship scheme. Resene's PaintWise programme accepts leftover paint and empty paint containers at participating Resene ColorShops around the country, often free for households up to a set volume. Water-based (acrylic) paint is recycled or repurposed, while solvent-based paints and the metal and plastic tins are handled appropriately. Before you go, let small amounts of leftover water-based paint dry out completely — once fully hardened, dried paint and the empty can may be accepted in general waste in some areas, but check with your local council first as rules vary.

Solvents such as mineral turps, methylated spirits, paint thinners, brush cleaner and old petrol or oil are genuinely hazardous and must never go in any kerbside bin. Keep them in their original, clearly labelled containers with the lids on tight, and take them to a transfer station or community recycling centre that runs a hazardous waste drop-off. Many councils hold regular or seasonal hazardous waste collection days, and some transfer stations have a permanent chemical drop point. A quick call or a look at your council website will tell you the nearest option and whether any fees apply.

Garden chemicals — weed killers, insecticides, fungicides, slug bait and old fertilisers — follow the same rule: they go to a hazardous waste facility, not the bin or the garden. Don't decant them into unmarked bottles, and never mix different chemicals together, as this can create dangerous reactions. If a product is still usable and within date, consider offering it to a neighbour, a community garden or a local buy-nothing group so it gets used rather than dumped. For unwanted or expired products, the transfer station hazardous drop-off is the safe route.

A little preparation makes the whole job easier. Store these products upright and out of reach of children and pets while they wait, keep everything in its original labelled container so staff know what they're handling, and transport them in the boot rather than the passenger cabin. Group your paint tins, solvents and chemicals together and plan one trip. The takeaway is simple: never bin it, never drain it, never bury it — check your local council or the PaintWise website, and take these materials to the proper drop-off so they're dealt with safely.