Proven Way: How To Get Asphalt Out Of Garbage Disposal

Immediate Action (First 5 Minutes)

Stop. Just stop right there. Don't touch that switch. If you're reading this, you or someone in your house just washed asphalt, driveway sealer, or roofing tar down the sink. I've seen this exact disaster unfold more times than I can count. My neighbor Dave washed his tar-covered squeegee in his utility sink last summer. The sticky black sludge went straight into his InSinkErator Badger 5 and jammed the impellers completely solid.

When you're dealing with petroleum-based binders like asphalt, introducing heat or mechanical force too early will only smear the sticky mess deeper into the grinding chamber. The absolute worst thing you can do is turn on the disposal. The motor will hum, overheat, and likely trip your internal reset button or blow a fuse.

Your first five minutes are critical. Turn off the water immediately. Grab a flashlight and peer down into the rubber splash guard. If you see black, tarry clumps clinging to the shredder ring, you have a mechanical lock. Do not run hot water. Hot water melts the tar, allowing it to travel down your pipes where it will cool and create a rock-hard clog in your P-trap. We want the asphalt frozen and brittle. Keep the sink dry and move to the next phase.

What You'll Need (Tools and Products)

I'll be honest, this takes elbow grease. You can't just pour a magical chemical down the drain and walk away. Asphalt requires mechanical extraction followed by chemical emulsification. I've tested dozens of solvents on my own workbench, and citrus-based degreasers are the only ones safe enough for your plumbing and disposal components.

Here is my exact toolkit for this messy job.

Item	Brand/Model	Estimated Cost	Purpose
Hex Wrench	InSinkErator 1/4" Jam-Buster	$4 - $8	Manually turning the flywheel
Citrus Solvent	De-Solv-It Pro-Power (12 oz)	$8 - $12	Emulsifying petroleum residue
Voltage Tester	Klein Tools NCVT-1	$20 - $25	Ensuring power is completely off
Pliers	Husky 11" Needle-Nose	$12 - $15	Extracting frozen tar chunks
Wet-Dry Vacuum	Ridgid 4-Gallon Portable	$60 - $80	Sucking up small debris

Let's talk about the hex wrench. Every InSinkErator model comes with a specific 1/4-inch hex wrench, often called a jam-buster wrench. If you lost yours, you can buy a replacement at Home Depot for about $4. Moen disposals use a similar Allen key setup. Don't try to use a screwdriver. You will strip the flywheel and ruin the unit.

For the solvent, I highly recommend De-Solv-It Pro-Power or Zep Commercial Citrus Degreaser. These cost between $12 and $18 per bottle. They contain d-limonene, which naturally breaks down petroleum bonds without eating through your PVC pipes or the rubber splash baffle. Avoid harsh paint thinners like acetone or raw mineral spirits. They can warp plastic plumbing joints and leave toxic fumes in your kitchen.

Step-by-Step Removal

Step 1: Kill the Power at the Breaker

Never trust a wall switch when your hand is about to go near the grinding chamber. I always go straight to the garage or basement and flip the 15-amp or 20-amp breaker that controls the kitchen sink. Grab a non-contact voltage tester and touch it to the disposal's power cord under the sink. If it beeps, you flipped the wrong breaker. Safety is non-negotiable here.

Step 2: Freeze the Asphalt Solid

Asphalt gets incredibly brittle at low temperatures. Fill a bowl with ice cubes and drop them directly into the disposal chamber. Let them sit for about 15 minutes. The freezing temperature shrinks the tar and pulls it away from the metal shredder ring. I've found that adding a cup of rock salt to the ice lowers the temperature even further, making the chunks snap off much easier.

Step 3: Manually Rotate the Flywheel

Grab your 1/4-inch hex wrench and insert it into the hexagonal hole on the very bottom center of the disposal unit. This is located underneath the sink. Crank the wrench back and forth. You'll feel heavy resistance at first. Keep pushing. The mechanical leverage will snap the frozen asphalt chunks right off the impellers. Work it until the flywheel spins freely in a full 360-degree circle.

Step 4: Extract the Chunks

Put on a pair of heavy-duty nitrile gloves. Reach into the chamber with long needle-nose pliers and pull out the broken shards of frozen tar. Drop them into a trash bag. For the smaller crumbles, I use the crevice tool on my Ridgid Shop-Vac. Suck out every last piece of debris. If you leave chunks behind, they will melt later and cause a secondary clog.

Step 5: Apply the Citrus Solvent

Now we tackle the thin, sticky residue coating the metal parts. Spray a generous amount of De-Solv-It directly onto the shredder ring and impellers. Let it sit for exactly 10 minutes. The d-limonene will emulsify the remaining petroleum bonds, turning the sticky tar into a wipeable sludge. Use an old toothbrush or a rag wrapped around tongs to scrub the inside of the grinding chamber.

Step 6: The Cold Water Flush

Reconnect the power at the breaker. Turn on your cold water tap to a moderate flow. Never use warm or hot water for this step. Flip the disposal switch. It should roar to life with a clear, aggressive hum. Let it run with the cold water for a full 60 seconds to flush the emulsified citrus sludge completely out of the drain line.

Alternative Methods

Sometimes the main method doesn't get every last drop of sticky residue, or you might not have citrus degreaser on hand. Here are two backup methods I've used in a pinch.

Method 1: WD-40 Specialist Solvent-Based Degreaser

Don't use regular WD-40. The standard formula leaves behind a lubricating oil film that will coat your pipes and attract future food debris. Instead, use the WD-40 Specialist Heavy-Duty Degreaser (the yellow and black can, usually $8 at auto parts stores). Spray it on the remaining tar spots, wait five minutes, and scrub with a stiff nylon brush. It cuts through driveway sealer exceptionally well. Just make sure you open a window, as the fumes are quite strong in an enclosed kitchen.

Method 2: The Dish Soap and Boiling Water Trap Flush

If you suspect some melted asphalt slipped past the disposal and is slowing down your P-trap, you need to clear the pipe. Squirt a half-cup of Dawn Ultra Platinum dish soap directly into the drain. Follow it with a full kettle of boiling water. The soap acts as a surfactant, while the heat melts the tar in the pipe. The rushing water pushes it through the 1.5-inch PVC trap. I only recommend this for the pipes below the disposal, never inside the disposal chamber itself.

Prevention Tips

If you're a DIYer who just finished sealing the driveway or patching a roof, listen to me closely. Never wash your tools in a sink connected to a garbage disposal. It's just not worth the $200 plumber bill.

I keep a dedicated 5-gallon Homer bucket in my garage specifically for washing tar and asphalt tools. Fill the bucket with hot water and a heavy-duty degreaser. Scrub your trowels, squeegees, and boots outside with a stiff-bristle brush. Let the dirty water sit overnight so the asphalt settles to the bottom. You can then carefully pour the clear water out onto your lawn and throw the hardened tar sludge in the trash.

Additionally, if you have kids who track mud everywhere, make sure they aren't scraping dried, tar-like driveway sealant off their shoes into the sink. A simple rubber sink strainer costs about $6 and will catch large debris before it drops into the grinding chamber.

FAQ

Can I use boiling water to melt the asphalt inside the disposal?

Absolutely not. Boiling water will melt the tar, but it will quickly cool and solidify inside your P-trap. This turns a simple disposal jam into a major plumbing emergency requiring a plumber's snake. Stick to cold water and mechanical removal inside the unit.

Will citrus degreaser damage the rubber splash guard?

Pure d-limonene can degrade certain rubbers over prolonged exposure, but a quick 10-minute application won't hurt your disposal's splash baffle. I always rinse the rubber guard thoroughly with cold water immediately after the solvent does its job. Just don't let the chemical sit in the chamber overnight.

What if the asphalt is stuck in the drain pipe below the disposal?

If the chunks bypassed the grinding chamber and lodged in your P-trap, you'll need to place a bucket underneath and unscrew the slip nuts. I keep a pair of 12-inch Channellock pliers specifically for loosening these PVC connections. Clean the trap out manually in a trash can before reassembling.