Proven Way: How to Get Tar Out of Garbage Disposal

By Amara Johnson · December 19, 2025

Immediate Action (first 5 minutes)

I learned this the hard way when my brother-in-law Mark decided to wash his driveway sealer brushes in my kitchen sink. He thought the running water would just carry the black sludge right down the pipes. Big mistake. The moment that viscous, petroleum-heavy sludge hit the cold stainless steel of the grind ring, it instantly seized the impellers. The motor hummed for exactly three seconds before the thermal overload protector tripped with a loud click.

If you are dealing with a similar disaster right now, stop what you are doing. Do not run the water. Water and tar do not mix, and adding moisture will only push the sticky mess deeper into the PVC P-trap. Turn off the wall switch immediately. Next, crawl under the sink and unplug the unit from the wall outlet. If your disposal is hardwired, go to your electrical panel and flip the breaker. You need to ensure zero power is reaching the motor while you work.

Grab a flashlight and peer down the drain. If you see thick, black clumps resting on the splash guard or the grind ring, you are dealing with a physical blockage. Don't panic. I've tested this exact removal process on my own InSinkErator Badger 5 after a roofing project went sideways, and it works beautifully if you act fast.

What You'll Need (tools/products)

You can't just scrub tar away with a sponge and some elbow grease. Petroleum-based stains require specific chemical solvents to break the molecular bonds. I'll be honest, the smell of mineral spirits in a closed kitchen is awful, so open a window before you start. Here is the exact gear I keep in my utility closet for these emergencies.

Kleen Strip Odorless Mineral Spirits ($14 for a quart): This is your primary weapon. It dissolves tar without eating through the metal components of your disposal.
WD-40 Specialist Heavy Duty Degreaser ($8): A great backup if you don't have mineral spirits on hand.
Dawn Platinum Powerwash Dish Spray ($6): You need a high-surfactant soap to emulsify the dissolved tar so it can flush down the drain.
12-inch Locking Pliers or Long Kitchen Tongs: Never put your bare hands down a disposal, even when unplugged. The shredder rings are razor-sharp.
InSinkErator Jam-Buster Wrench: This 1/4-inch hex wrench usually comes taped to the bottom of the unit when you buy it.
OXO Good Grips Stiff-Bristled Nylon Brush ($7): Wire brushes will scratch the stainless steel and cause rust. Stick to stiff nylon.
MicroFlex Black Dragon Nitrile Gloves ($25 for a box of 100): Tar will stain your skin for weeks. Wear heavy-duty gloves.

Solvent Comparison Table

Solvent Type	Effectiveness on Tar	Odor Level	Avg Price
Mineral Spirits	Excellent (Fastest)	Moderate	$12 - $16
Citrus Degreaser (d-Limonene)	Good (Slower)	Low (Pleasant)	$8 - $12
WD-40 Specialist	Very Good	High (Chemical)	$7 - $10

Step-by-Step Removal

When your landlord inspects next week, or you just want your kitchen back to normal, follow this exact sequence. I've refined this 5-step method over 10 years of cleaning up DIY disasters.

Step 1: Dry Extraction

Put on your nitrile gloves and grab your 12-inch tongs. Reach into the disposal and pull out any large, solid chunks of tar, roofing felt, or driveway sealer. Drop them directly into a heavy-duty plastic trash bag. Do not try to wash these large pieces down the drain. They will simply melt and re-clog your P-trap further down the line. Get out as much physical mass as humanly possible before introducing any liquids.

Step 2: Apply the Solvent

Pour exactly 1 cup of Kleen Strip Mineral Spirits directly into the disposal chamber. Make sure the liquid coats the rubber splash guard flaps and pools over the stainless steel grind ring. Now, walk away. Let the solvent sit for a full 20 minutes. This dwell time is absolutely critical because the chemicals need time to break down the heavy hydrocarbon chains in the tar. If you rush this step, you'll just be pushing sticky sludge around.

Step 3: Manual Rotation

Crawl under the sink and locate the small hexagonal hole in the exact center of the disposal's bottom casing. Insert your InSinkErator Jam-Buster Wrench. Turn the wrench back and forth aggressively. You are manually rotating the impeller plate to break the suction seal and work the solvent into the hidden crevices. When the wrench spins freely in full 360-degree circles, the physical jam is cleared.

Step 4: Scrub the Grind Ring

Go back to the top of the sink. Dip your OXO stiff-bristled nylon brush into the solvent pool. Scrub the inside walls, the rubber splash guard, and the outer grind ring. You'll notice the black tar turning into a thin, brownish liquid. Wipe the brush clean on a paper towel and repeat until the stainless steel shines.

Step 5: The Emulsion Flush

This is where the magic happens. Boil a full kettle of water (around 212°F). Squirt a generous amount of Dawn Platinum Powerwash directly into the disposal. Turn on the cold water tap to a moderate flow. Turn on the disposal. Slowly pour the boiling water down the drain while the unit is running. The extreme heat, combined with the heavy surfactants in the Dawn soap, will emulsify the remaining dissolved tar and carry it safely through your plumbing.

Alternative Methods

If you don't have mineral spirits, or if you're dealing with a sensitive septic system, try these backup strategies. They take a bit more time, but they get the job done.

The Citrus Solvent Soak

Products containing d-Limonene, like Zep Citrus Degreaser or De-Solv-it, are fantastic natural alternatives. They smell like oranges instead of a chemical plant. The trade-off is that they work much slower. You'll need to let the citrus solvent sit for at least 45 minutes to penetrate hardened tar. I recommend using this method if you have kids who track mud everywhere and you want to avoid harsh fumes in the house.

The Ice and Rock Salt Grind

This method only works for minor tar smears, not massive blockages. Fill the disposal chamber with 2 cups of ice cubes and 1 cup of coarse rock salt. Turn on the cold water and run the disposal. The ice acts as a blunt hammer to knock debris off the impellers, while the rock salt acts as an abrasive scrubber against the grind ring. It won't dissolve petroleum, but it will physically scrape away residual film.

Prevention Tips

The absolute best way to handle tar in a garbage disposal is to never put it there in the first place. I know that sounds obvious, but you'd be surprised how many people try to wash pine tar off baseball bats or asphalt sealant off rollers in their kitchen sink.

Use a Utility Sink: If you must wash tools indoors, use a deep laundry tub or utility sink that does not have a garbage disposal attached. The wide, open drain pipe is much less likely to clog.
The Bucket Method: After hosting a dinner party or finishing a weekend DIY project, wash your tar-covered tools in a 5-gallon plastic bucket filled with hot water and degreaser outside. Let the sludge settle to the bottom, then pour the clean water onto your lawn.
Scrape First: Always use a putty knife to scrape 95% of the solid tar into the trash before the tool ever touches water.

FAQ

Will tar ruin my disposal motor?

Tar itself won't permanently destroy the motor if you catch it early. However, the seized impellers will cause the motor to overheat and trip the internal thermal overload switch. Once you clear the physical blockage and press the red reset button on the bottom of the unit, it should run perfectly fine.

Can I use bleach to dissolve the tar?

Absolutely not, because bleach does absolutely nothing to break down petroleum-based products like tar or asphalt sealer. Mixing bleach with other cleaning agents or solvents can also create toxic chloramine gas in your enclosed kitchen space. Stick to the mineral spirits or citrus degreasers I recommended above.

What if the tar has already hardened into a solid block?

Hardened tar requires a much longer dwell time with your solvent, sometimes up to 45 minutes. You will need to manually chip away the top layer using a flathead screwdriver and a hammer before the liquid solvent can penetrate the lower layers. I'll be honest, this takes serious elbow grease and might require repeating the solvent soak two or three times.

Is it safe to put mineral spirits down the drain?

Small amounts of mineral spirits flushed with massive volumes of water and dish soap are generally safe for municipal sewer systems. However, if you are on a private septic system, you should bail the dissolved tar sludge out with a cup and dispose of it at a local hazardous waste facility. Never pour raw, undiluted solvents directly into your plumbing.