How to Clean a Range Hood Filter (Without Replacing It)
By Priya — deep-clean specialist, Sydney inner-west.
Pull the filter out of any range hood that hasn’t been cleaned in six months and you’ll find a slab of brown grease so thick it looks like a different material. Most people, when they get to this point, do one of two things: throw the filter away and order a new one ($60-80 at appliance parts stores), or worse — hit it with caustic oven cleaner and ruin it.
Both are wrong. Aluminium mesh filters — which is what 95% of Aussie kitchen range hoods use — clean back to factory in 20 minutes with materials you’ve already got: boiling water, bicarb, and a dishwashing tablet. The trick is the laundry trough method: filter goes in flat, water goes in hot, chemistry does the work, you do nothing for 20 minutes.
The Aussie gotcha — and this is what trips people up who watch US YouTube videos — is that American range hoods often use HEPA carbon filters (replaceable cardboard-and-charcoal cartridges). Aussie range hoods almost universally use washable aluminium mesh. The cleaning method for those two is completely different. Pour caustic oven cleaner on aluminium mesh and you pit it permanently — the mesh corrodes through within a year and you’ve written off an $80 part.
What you’ll need
- Boiling water — full kettle, plus a saucepan if your trough is big
- Bicarbonate of soda — half a cup. Cheap supermarket bicarb is fine
- One dishwashing tablet — Finish Quantum or Fairy or supermarket brand
- Laundry trough or a deep tub (your kitchen sink works in a pinch — use a basin to protect the sink finish)
- A nylon dish brush or old toothbrush
- Microfibre cloth
- Newspaper or an old towel for the floor (drips)
- Rubber gloves
- NEVER: oven cleaner, caustic soda, ammonia, bleach
Step 1: Identify the filter type before you start
This is critical. Open the range hood, slide out the filter (usually a button or clip releases it). Look at it:
- Silver/grey aluminium mesh — multiple layers of crinkly mesh: Washable. Use this method. 95% of Aussie hoods.
- Black/dark grey carbon filter — looks like a thick cardboard pad with foam: Not washable. Replace it. Common in some recirculating (non-ducted) hoods only.
- Stainless steel baffle filter — interlocking metal blades: Washable, dishwasher safe. Use the same method but skip the dishwashing tablet (it can dull stainless).
If yours is carbon, stop here and order a replacement. If yours is aluminium mesh or stainless baffle, continue.
Step 2: Lay newspaper around the trough
Hot greasy water will splash. Newspaper or an old towel saves the laundry floor. Take the trough’s plug out and replace it with a fresh seal — most laundry trough plugs are knackered and let the hot water drain mid-soak.
Step 3: Boil the kettle and bring water to the trough
You want the filter fully submerged. Start with a kettle of just-boiled water, then top up from the hot tap until the filter is covered with at least 30 mm of water above it. Boiling water is what drives the grease out — lukewarm water won’t do it.
Step 4: Add bicarb soda first, then the dishwashing tablet
Half a cup of bicarb sprinkled over the surface — it’ll fizz on contact with the hot water. Then drop the dishwashing tablet in. The tablet contains enzymes and surfactants that break down baked-on grease, exactly the chemistry you’d use in the dishwasher for greasy plates. Together with the bicarb, you’ve got an alkaline degreaser that’s strong enough to lift years of grease but mild enough to leave aluminium intact.
Step 5: Submerge the filter flat
Lay the filter flat in the trough, mesh-side up. The flat orientation matters — water needs to reach all the layers of the mesh. Filters propped vertically only get the lower portion cleaned and you’ll have a half-clean filter at the end. Push it down so it’s fully under the water surface.
Step 6: Walk away for 20 minutes
This is the bit nobody believes. You don’t scrub. You don’t agitate. You walk away. Make a coffee. Empty the dishwasher. Come back in 20 minutes and the water will be brown — sometimes opaque brown — and the filter will be most of the way clean already.
For really horror filters (haven’t been cleaned in 2+ years), top up with another kettle of boiling water at the 20 minute mark and leave another 15 minutes. The water needs to stay hot to keep the chemistry working.
Step 7: Drain and inspect
Pull the plug. Lift the filter out — careful, the mesh can be hot and the filter will drip. Hold it under the hot tap and rinse front and back. Most of the grease will sluice off. Hold it up to the light. You should see light through the mesh in every cell — that means the airflow path is clear.
Step 8: Detail the corners with a brush
The corners and the edge frame often have stubborn deposits the soak didn’t fully shift. Nylon dish brush or old toothbrush, with a sprinkle of fresh bicarb on the bristles, scrub the corners specifically. This is where the burnt-on stuff lives. Rinse again under hot water.
Step 9: Dry thoroughly before refitting
Pat dry with a microfibre, then sit the filter on a draining rack or hang it over the trough for an hour to fully air-dry. Wet aluminium against the plastic mounting clips of the range hood corrodes both — so dry it properly. Don’t put it back wet.
Step 10: Wipe the inside of the hood while you’re there
With the filter out, you’ve got access to the fan housing and the inside of the hood. A microfibre cloth with a spray of Spray & Wipe (or another mild kitchen degreaser like Gumption — but go gentle, Gumption is mildly abrasive) wipes the housing clean. Don’t get water into the fan motor or the light fitting — wring the cloth out properly. Refit the dry filter when you’re done.
The dishwasher shortcut — does it work?
Yes — for stainless baffle filters, the dishwasher on a hot wash with rinse-aid will clean them perfectly. Lay them flat on the bottom rack so the spray reaches both sides. For aluminium mesh, the dishwasher works but it’ll dull the aluminium to a matte finish over time (cosmetic only — the filter still works). The trough method preserves the original sheen better because the contact time with hot detergent is shorter and gentler.
Don’t put a carbon filter in the dishwasher. Obviously. The cardboard core disintegrates in 30 seconds and you’ll be unblocking the dishwasher pump.
What about the grease that’s escaped past the filter?
Once the filter is clean, look at the inside of the hood housing, the fan blades and the duct outlet. If any of those are coated in grease, your filter has been so blocked that grease has bypassed it for months. Wipe the housing and fan blades with a microfibre and warm soapy water. The duct itself — the metal pipe up to the roof — usually doesn’t need cleaning unless you’re doing a full hood replacement. Greasy ducts are a fire risk in commercial kitchens but in domestic settings they rarely cause problems.
If your hood vents through a kitchen cupboard back to room (a “recirculating” hood), the carbon filter inside that unit needs replacement annually. They’re $30-50 a pair from Appliances Online or directly from the hood manufacturer. The carbon binds odours; once saturated, the hood just blows warm greasy air back into the kitchen.
How often is “regularly”?
- Heavy cooking household (Asian wok cooking, frequent frying, daily dinner cooking): every 4-6 weeks
- Average cooking (cooks 4-5 dinners a week, occasional frying): every 3 months
- Light cooking (eats out often, mostly microwave/oven): every 6 months
The honest test: pull the filter out and hold it up to a window. If you can’t see clear daylight through the mesh, it’s overdue. A clean filter has substantial airflow visible through it; a clogged one looks solid.
Why a clean filter actually matters
Beyond aesthetics, a clogged range hood filter is a measurable fire risk. Trapped grease lining the filter and the duct above is exactly the fuel a stovetop fire wants to climb into. Aussie home insurance claims for cooking fires often cite filter cleanliness in the assessment. A 20-minute filter clean every 3 months is not just neat-freak behaviour — it’s genuine fire prevention. Same reason commercial kitchens are required by law to have their hoods cleaned quarterly: not for hygiene, for fire prevention.
The Priya rule
Aluminium mesh filter, 20 minutes, boiling water + bicarb + a dishwashing tablet. No oven cleaner, no caustic soda, no scrubbing. Identify the filter type before you start so you don’t try to wash a carbon filter (impossible) or chemically attack stainless (avoidable). Schedule it every 3 months for active kitchens, every 6 months for households that mostly eat out, and the filter never gets bad enough to be a half-day chore. The chemistry does the work — you just walk away and let it.
Got a hood with a filter type not on this list, or grease that didn’t shift even with the soak? Send us a write-up.
