Advice
How to clean extractor fan filters
East Cambs Oven Cleaning, Burwell, Cambridgeshire. Checked 15 September 2026.
The short answer
How do you clean extractor fan filters? Take the metal ones out and soak them flat in the hottest water your tap gives, with washing up liquid, for twenty minutes. Not the dishwasher: it turns aluminium mesh chalky grey. A carbon filter is never cleaned, it is replaced.
First, which filter have you got?
Every hood has a metal mesh filter, and it is the one you can see from underneath: layers of fine aluminium or stainless mesh in a frame, held by a catch. That is the one that soaks, and it lasts for years if it is looked after. Having the hood done with the oven is £20, and the price list has the rest of it.
Some hoods have a second one behind it. If yours vents back into the room rather than out through a wall, there is a carbon filter in there absorbing the smells, and carbon cannot be washed. Once it is full it is replaced rather than cleaned, and how often that comes round depends on how much frying goes on, so the maker's guide is the one to go by. Washing one does nothing except make it wet.
The soak, step by step
Half an hour, most of which is the filters sitting in the sink while you do something else.
Turn it off at the wall first
Not the button on the hood, the switch on the wall or the isolator. You are about to put a hand near a fan, and lights inside a canopy get hot enough to burn.
Drop the filters out
Most have a sprung catch or a small handle on the underside. Push and let the filter hinge down rather than pulling it, because the frames bend and then they rattle for the rest of their life.
Soak them flat in the hottest water the tap gives
Washing up liquid, or a degreaser if the mesh is properly loaded, and give it twenty minutes rather than two. Grease inside a mesh does not come out with a wipe, it comes out when it lets go of the metal.
Rinse both faces and dry them properly
A wet filter refitted over a hob drips onto the pan below and streaks the canopy you just cleaned. Shake them, stand them on a towel, and leave them until they are dry to the touch.
Do the canopy while the filters are out
This is the part almost nobody does, and it is the part that smells. The grease trap above the filters and the inside of the canopy collect the same grease, and with the filters out you can reach both with a cloth.
The dishwasher is the advice that ruins the filter
It is the quickest way to do it, and on an aluminium mesh filter it is the one thing that does permanent damage. Dishwasher detergent is strongly alkaline, far harsher than washing up liquid, and it attacks the aluminium rather than the grease sitting on it. The filter comes out dull, chalky and grey, and it stays that way for the rest of its life.
Stainless steel mesh takes it better, and most people cannot tell which they have without looking at the frame. A sink of hot water costs nothing, gets more grease out of either kind, and ruins neither.
How to tell when a filter is finished
Soak it, dry it, then hold it up to a window or a light. If daylight comes through the mesh evenly, it is clean and it will go on for years. If the middle is dark while the edges glow, the grease has set between the layers of mesh and no amount of soaking is getting it out. That filter is a part now, rather than a job, and a new mesh is a few pounds against a hood that pulls nothing and smells anyway.
It is the test we use on every hood we open, and it is the reason we will tell you a filter needs replacing rather than charging you to clean it again.
Or have it done with the oven: £20 for the hood, filters soaked and the canopy by hand, while we are already in the kitchen.
Get a priceWhat the sink cannot get to
Filters soaked and a cloth round the canopy is most of the job, and it is worth doing. These are the parts left after that. Ductwork inside the wall or the ceiling is a different trade with different equipment, and in a domestic kitchen it is rarely what is causing the smell.
- The grease trap on the hoods where it does not lift out, which is where the smell sits
- Inside the chimney section above the canopy, on a 90cm hood or an island one
- A carbon filter that is full, because it is replaced rather than cleaned and most people do not know theirs is there
- Knowing which of those three is causing the smell, which is the part that saves you buying the wrong thing
An extractor is £20 alongside an oven clean, or £30 for a hood 90cm or wider, with the filters soaked, the trap and the canopy done by hand, and the carbon filter identified if there is one. Booked on its own a standard hood is £30 and a 90cm one £40, and the £65 minimum applies to a visit with no oven in it. The detail is on the extractor hood page, and whether paying somebody is worth it has the arithmetic for the kitchen as a whole.
Questions about extractor filters
Can I put extractor filters in the dishwasher?
You can, and an aluminium mesh one usually comes out chalky grey and stays that way. Dishwasher detergent is strongly alkaline and it attacks the aluminium itself rather than the grease on it. Stainless steel mesh survives it better, but a sink of hot water and washing up liquid gets more grease out of either of them and ruins neither.
How often do extractor filters need doing?
Hold one up to a light rather than looking at a calendar. If daylight comes through the mesh evenly, it is fine. If the middle has gone dark, the grease is sitting inside the layers and it is due. Somebody frying most nights will be looking at that every few weeks, and somebody who boils pasta twice a week will not.
Why does my extractor still smell after I have cleaned the filters?
Because the filter is the part you can reach and not the part that holds the smell. Grease collects in the trap above the filters and on the inside of the canopy, and a recirculating hood also has a carbon filter that absorbs odour until it is full, at which point it is replaced rather than cleaned.
Can I run the hood with the filters out?
Not for long. The metal filter is the only thing between your frying pan and the fan, so with it out the grease goes straight onto the impeller and into the duct, where nothing you own can reach it. If a filter is soaking, leave the extractor off until it is back in.
What does it cost to have the extractor done with everything else?
Done in the same visit as the oven it costs £20, or £30 for a hood 90cm or wider, which is how most people have it done because we are already in the kitchen with the tank hot. By itself it is £30, or £40 for the 90cm size, and a visit with no oven in it has the £65 minimum on it.
Filters soaked, canopy done, £20 with an oven clean
Hood, filters and trap while the oven is being done, in one visit rather than three. East Cambridgeshire and west Suffolk from Burwell, Cambridgeshire, no VAT, and no travel charge inside 12 miles.
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