Tested Guide: How to Get Tar Out of Exhaust Fan Fast

By Amara Johnson · December 18, 2025

Immediate Action (first 5 minutes)

Grab a plastic scraper. You want to remove the thickest layers of hardened grease before introducing any liquids, which just turns the mess into a slippery nightmare. Scrape it dry. If you just noticed this sticky disaster after frying bacon all weekend, don't panic. I've cleaned hundreds of these units over the last decade, and catching it early saves you hours of scrubbing.

First, kill the power. Flip the breaker or unplug the unit entirely. I once shocked myself pretty badly because I forgot to cut the juice before wiping down the motor housing with a wet rag. Don't make that mistake. Next, pull the metal mesh filters out of the tracks. Set them on a layer of paper towels on your counter. If the tar is still warm and slightly tacky, use a rigid plastic putty knife to gently push the bulk of the residue into the trash. Never use metal scrapers on aluminum mesh. You'll tear the delicate screen and ruin a $15-25 replacement part before you even start cleaning.

What You'll Need (tools/products)

I'll be honest, this takes elbow grease. You can't just spray and wipe away months of polymerized cooking oils. Over the years, I've tested dozens of degreasers, and I've narrowed it down to a specific toolkit that actually works without melting your kitchen fixtures.

Item	Purpose	Estimated Cost
Krud Kutter Original	Breaks down polymerized tar	$8-12
Dawn Platinum Powerwash	Emulsifies grease in hot soaks	$4-6
Nylon Grout Brush	Agitates mesh without tearing	$5-8
Plastic Putty Knife	Scrapes bulk residue safely	$3
Microfiber Cloths (Pack of 12)	Wipes down housing and motor	$10-15

I highly recommend the Krud Kutter Original formula for the heavy lifting. This isn't the cheapest option, but it eats through carbonized tar that standard all-purpose cleaners just smear around. For the initial hot soak, Dawn Platinum Powerwash is unmatched. The enzymes in it literally chew through the lipid bonds of the cooking oil. Finally, get a stiff nylon grout brush. The bristles are short and rigid enough to push through the tiny diamond holes of a Broan-NuTone mesh filter without bending the aluminum frame.

Step-by-Step Removal (4-7 steps)

Step 1: The 140°F Hot Soak

Boil a large pot of water or run your kitchen tap until it hits about 140°F. You need serious heat to soften the tar. Place your metal mesh filters in a large roasting pan or your kitchen sink. Pour the hot water over them until they are completely submerged. Squirt a generous amount of Dawn Platinum directly onto the worst tar spots. Let them sit for exactly 20 minutes. The water will turn a murky, disgusting brown. That means it's working.

Step 2: Apply the Heavy-Duty Degreaser

Pull the filters out of the soak and let the excess water drip off. Spray the Krud Kutter heavily over both sides of the mesh. Don't be shy with it. I usually go through about half a bottle for a heavily soiled dual-filter setup. Let the chemical sit for 10 to 15 minutes. You'll actually see the tar start to wrinkle and lift away from the metal.

Step 3: Agitate the Mesh

Take your nylon grout brush and start scrubbing. Work in small, circular motions. Push the bristles directly into the mesh holes to force the dissolved gunk out the other side. Flip the filter over and repeat. If you hit a stubborn patch of black crust, spray a little more degreaser and let it sit for another five minutes before attacking it again.

Step 4: Clean the Fan Housing

While the filters are drying, tackle the actual fan unit. Spray your microfiber cloth with Krud Kutter. Never spray directly into the motor housing. Liquid will seep into the electrical windings and fry the capacitor. Wipe down the interior metal baffles, the light sockets, and the exterior plastic cover. Use a cotton swab dipped in rubbing alcohol to clean the tight corners around the light bulb sockets.

Step 5: Rinse, Dry, and Reassemble

Rinse the filters under warm running water until the water runs completely clear. Shake off the excess moisture. Dry them thoroughly with a clean towel or let them air dry in the sun for 30 minutes. Moisture left in the mesh will attract dust and create a new layer of grime almost immediately. Once bone dry, slide them back into the tracks and restore power.

Alternative Methods (2-3 backup methods)

Method 1: The Boiling Pot Technique

If your sink isn't deep enough for a proper soak, use your largest stockpot. Fill it with water, add a half-cup of baking soda, and bring it to a rolling boil. Drop the metal filters in one at a time. Boil them for 10 minutes. The intense 212°F heat combined with the alkaline baking soda will melt the tar right off the aluminum. I use this method when my landlord inspects next week and I need the filters looking brand new. Just be careful not to bend the frames when dropping them in.

Method 2: Mineral Spirits for the Motor Casing

Sometimes tar builds up on the painted exterior or the metal flapper valves outside the house. Dish soap won't touch it. Dampen a rag with mineral spirits and wipe down the exterior painted surfaces. The solvent breaks down the sticky residue in seconds without stripping the paint. Make sure you open a window for ventilation. The fumes are no joke.

Method 3: Easy-Off Oven Cleaner (Metal Only)

This is my absolute last resort. If the tar has baked on for years and turned into a hard, black shell, spray the metal mesh filters with Easy-Off Heavy Duty. Let it sit for 5 minutes, then hose them off outside. Do not use this on plastic parts or the motor housing. The lye in the oven cleaner will permanently cloud and warp plastic in minutes. It's harsh, but it works on neglected metal.

Prevention Tips

Stopping tar before it hardens is a million times easier than scraping it off later. I recommend pulling the filter and giving it a quick wash every single month if you cook daily. If you only cook a few times a week, a deep clean every three months will keep the tar from cementing itself to the mesh. Setting a recurring reminder on your phone for the first Sunday of the month works best for my own schedule.

Invest in a splatter screen for your frying pans. When you're searing steaks or frying chicken, a $12 mesh splatter guard catches the heavy airborne grease droplets before they ever reach the ceiling. It keeps your cabinets, your walls, and your exhaust fan remarkably clean. Also, always turn your fan on five minutes before you start cooking. Letting it establish a strong draft early pulls the grease vapor straight up into the filter rather than letting it drift and settle on the fan's exterior plastic housing.

FAQ

Can I put the exhaust fan filter in the dishwasher?

You technically can, but I strongly advise against it. The high heat and harsh dishwasher detergents will strip the protective aluminum coating right off your mesh filter. I learned this the hard way when my Broan-NuTone filter turned completely black and started flaking. Stick to the manual soaking method I outlined above to keep your gear intact.

Will tar ruin the exhaust fan motor?

Yes, heavy tar buildup will eventually seize the motor bearings and burn out the unit. I've seen fans completely stop working because the sticky residue crept past the filter and glued the internal blades to the housing. If you notice your fan rattling or struggling to pull air, you need to clean it immediately before the motor shorts out.

How often should I clean the fan to prevent tar buildup?

I recommend pulling the filter and giving it a quick wash every single month if you cook daily. If you only cook a few times a week, a deep clean every three months will keep the tar from hardening into a cement-like shell. Setting a recurring reminder on your phone for the first Sunday of the month works best for my own schedule.

Is it safe to use oven cleaner on the plastic fan cover?

Absolutely not, unless you want to melt the plastic housing. Oven cleaners like Easy-Off contain lye, which will permanently cloud, warp, and weaken plastic components in just minutes. Only use heavy-duty degreasers on the bare metal mesh filters, and stick to mild dish soap for the plastic or painted exterior covers.