how do you clean the fins on this thing? dust is packed in there and it smells when it heats up

Diagnosis

The burning smell you are experiencing is caused by the combustion of organic particulate matter—primarily household dust, pet dander, and microscopic fabric fibers—that has settled into the narrow gaps between the heating fins of your De'Longhi TRD40615E. Because this is an oil-filled radiator, the heat is transferred from the internal oil to the external steel casing. When the surface temperature reaches a critical threshold, the accumulated dust undergoes a process called pyrolysis, where it chemically decomposes and releases volatile organic compounds (VOCs) into the air. This buildup is particularly aggressive in the lower sections of the unit where heavier dust particles settle and in the narrow crevices between the vertical fins. If left uncleaned, this layer of dust acts as an insulating blanket, trapping heat within the steel casing and forcing the internal thermostat to work harder, which can eventually shorten the lifespan of the heating element. You can confirm this is the issue if the smell is most pungent during the first 30 minutes of operation or if you see visible grey "clumping" in the gaps between the fins.

How to Fix It

To thoroughly clean the fins without damaging the powder-coated finish or compromising the internal seals, follow this precise sequence:

1. Complete Power Down: Unplug the unit from the wall outlet. Wait at least 3 hours for the internal oil to cool completely. Attempting to clean a warm unit can cause the damp cloth to steam-clean dust deeper into the crevices.
2. Initial Dry Extraction: Set your vacuum cleaner to the lowest suction setting to avoid denting the fins. Attach the soft-bristle brush nozzle. Insert the nozzle into the gaps between the fins, moving in a strict top-to-bottom motion. Do not scrub horizontally, as this can push dust clumps further down into the base.
3. Deep Crevice Clearing: For the tight spaces near the bottom tray and the control panel, use a can of compressed air. Hold the can strictly upright to prevent liquid propellant from spraying onto the heating elements. Use short, 1-second bursts to blow dust outward from the center of the unit toward the edges where the vacuum can reach it.
4. Detailed Wipe-Down: Dampen a lint-free microfiber cloth with warm water and a drop of mild dish soap. Wring it out until it is barely damp (not dripping). Carefully wipe the exterior surface of each fin. Avoid using any abrasive sponges or steel wool, as these will scratch the coating and lead to rust.
5. Final Dry: Use a separate dry microfiber cloth to wipe away any remaining moisture. Let the unit air dry for 30 minutes before plugging it back in.

If That Didn't Work

• Use a Fin Comb or Soft Brush: If the dust has become "caked" or sticky due to kitchen grease or humidity, a vacuum alone won't work. Use a soft-bristled paintbrush or a dedicated radiator brush to manually loosen the debris while simultaneously holding the vacuum nozzle an inch away to catch the particles as they fly.
• Isopropyl Alcohol Treatment: For stubborn, sticky residue that smells like burnt oil, dampen a cotton swab with 70% Isopropyl Alcohol. Gently rub the affected spot on the fin, then immediately wipe it clean with a damp water-cloth. This breaks down the oils without damaging the paint.
• Check the Base Vent: Ensure the bottom tray and the area where the cord exits are clear of lint. Dust often accumulates in the bottom channel and gets sucked upward by convection currents, recirculating the smell. Vacuum the underside of the unit as well.
• Controlled Burn-Off: If the smell persists after a deep clean, place the heater in a well-ventilated room (open windows) and run it on the maximum setting (Level 3) for 2 hours without anyone in the room. This will burn off the remaining microscopic residue that cannot be physically reached.

Heads Up

• Avoid Chemical Sprays: Never spray cleaning agents, furniture polish, or air fresheners directly onto the fins. These chemicals can bake onto the surface, creating a permanent sticky film that attracts more dust and smells worse when heated.
• No Water Immersion: Never attempt to wash the unit in a shower or use a soaking wet cloth near the control dial and power switch, as this can cause a short circuit in the thermostat.
• Placement Matters: To reduce future buildup, keep the heater at least 3 feet away from curtains, bedding, or laundry piles, which are the primary sources of the lint and dust that clog the fins.
• Seasonal Maintenance: Perform this cleaning process once every autumn before the first use of the season to prevent the "first-heat smell" and maintain energy efficiency.