Soak the aluminium mesh filters flat in hot water with a non-caustic degreaser rather than putting them through a dishwasher. On a DeLonghi of typical age the more important question is the ducting above, which has had fifteen to twenty five years of vapour through it.
DeLonghi hoods went into Sydney apartments and townhouses alongside DeLonghi ovens and hobs through the 2000s and 2010s. The general method, filters out, soaked flat, then the impeller housing behind them, is on our rangehood cleaning guide. What is worth thinking about on this brand is age rather than engineering.
Two decades of duct
A hood installed in 2007 has had close to twenty years of cooking vapour passing through its duct. Some of that fat condenses on the duct wall and hardens, layer on layer, and nobody has ever seen it because the duct disappears into a ceiling or a wall cavity and there is no reason to look.
Two things follow. A duct partly lined with hardened fat moves noticeably less air, so the hood runs while doing progressively less, and the decline is slow enough that nobody notices it happening. And a duct heavily lined with fat is a genuine fire risk, which is why commercial kitchens have theirs cleaned on a schedule and domestic ones almost never do.
You can wipe as far up as your arm reaches with the filters out. Beyond that it needs equipment, and on a hood of this vintage it is worth having looked at rather than assumed.
The filters, and whether they are worth saving
DeLonghi used aluminium mesh on most models. On a hood that has run for fifteen years without a soak, a mesh filter is frequently past recovery: the layers have loaded solid and no amount of soaking will clear the interior.
That is not a failure of the clean. It is a filter that has done its job for far longer than it was meant to, and replacing it costs a fraction of what letting the fan do the filtering costs. If a soak does not visibly clear it, replace it.
It is one of three
DeLonghi kitchens were supplied as sets, so the hood, hob and oven are the same age. The hood is invariably the one furthest behind, because it never fails outright, and it is the reason the other two keep getting greasy. See how to clean a DeLonghi oven and how to clean a DeLonghi cooktop.
What actually goes wrong
Ducting nobody has inspected in two decades.
Filters that have loaded solid and are past soaking.
Grey mesh from a dishwasher cycle.
A hood never opened across two or three owners.
Should you do it yourself?
Do it yourself for the filters, and replace rather than persist if a soak does not clear them.
Get someone in for the impeller housing and, on a hood of this age, to establish what the duct actually looks like.