Most of us store cleaning supplies wherever there's room - I know I do, especially in a tiny big metropolitan flat. Under the kitchen sink, in whatever cabinet has space, even using storage as decor. But where your sprays and scrubbers live has a real effect on how often you actually use them, how long they last, and, in a few cases, whether they damage your home.

I asked professional organisers who’ve emptied hundreds of houses, as well as Noah Pinsonnault of the Good Housekeeping Institute Home Care & Cleaning Lab US, where cleaning supplies belong—and where they absolutely don't. Here’s what the experts say:

The best place to keep cleaning supplies

Every expert I talked to landed on the same piece of hardware: a caddy, stored somewhere cool, dry and easy to reach.

'Cleaning supplies should be kept close to where you use them so you can grab and go,' says Karen Larkin, who cleaned homes for seven years before founding Belle Home. 'When it's time to clean, you don't want to slow yourself down by having to go through cabinets and drawers to find what you need.'

Andrew Brown, owner of Immediate Movers and Storage, sorts by task rather than by product type. Each caddy holds only what that room uses: glass cleaner, disinfectant spray, a scrub brush and paper towels in the bathroom; washing-up liquid, all-purpose spray, a sponge and a small trash bag in the kitchen. Anything that doesn't belong to a single room goes in a hall cupboard.

His rule for what not to do? 'A caddy with too much in it is basically a junk drawer wearing a nicer outfit.'

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The worst place to keep cleaning supplies

The garage.

'I used to think it was fine too, until I saw what a Northwest Indiana summer does to a sealed-up garage,' Brown says—he's pulled bottles from client garages with peeling labels and bulging seams.

Pinsonnault's rule covers why: keep cleaning products somewhere cool and dry, away from temperature extremes, and follow the label's storage instructions. Heat can accelerate degradation in some products and raises pressure inside aerosol containers. Cold can affect some formulations too, which makes an unheated garage a problem in both directions.

Bleach is the sneakier casualty, gradually losing active chlorine over time, with heat speeding that up. Oxygen-based products lose potency as well—sodium per-carbonate, the oxygen bleach in many powdered cleaners, loses available oxygen faster in moisture and high heat. Basements bring their own problem: high humidity can compromise packaging and is especially hard on powdered products that need to stay dry.

So how do you know something's past it? 'A change in appearance, odour or consistency, or damaged or swollen packaging can be a reason to replace a product,' Pinsonnault says. But some cleaners lose efficacy without any visible change, and shelf life varies by formulation, so check the manufacturer's guidance.

What about under the sink?

It's the most popular spot in the house and the riskiest. Brown says he's pulled apart roughly 40 cabinets where a bottle leaked around a pipe and the homeowner didn't know until moving day. If it's your only option, he suggests layering defences: a bin to catch leaks, a riser to keep bottles off the cabinet floor and a liner underneath. Then check the cabinet every couple of months.

There's a bigger reason to think twice. 'If you have young children or pets, safety should come before convenience,' Pinsonnault says. Keep products in their original containers, somewhere kids and pets can't reach - and if a low cabinet is unavoidable, secure it with an appropriate child-safety lock.

How many products do you actually need?

Fewer than you have. 'I see that people purchase too many cleaning supplies,' Cathy Orr says, a master consultant in the KonMari Method® with more than 20 years of organising experience. 'Many supplies can do double duty. If you only purchase a few, you're bound to use them up.' She owns about 10, total: washing-up liquid, dishwasher pods, a counter spray, toilet bowl cleaner, a stainless steel cleaner and a wood cleaner.

She adds one non-negotiable - pick something that smells good to you. 'Use a scent that you love and makes you feel happy. To me, that sparks joy.'