How to clean and unclog a garbage disposal
A clean, free-spinning disposal in about 20 minutes: how to clear odors, free a jam, fix a clog under the unit, and what to keep out of it for good.
Written by Illyrian Plumber
Expert ReviewedLicensed Master Plumbers
NJ Licensed Master Plumber | 10+ Years Experience | Serving Middlesex County, NJ
A garbage disposal that smells, hums, or backs up is one of the most common kitchen complaints, and most of the time you can fix it yourself in under 20 minutes. The repairs below are the same ones our kitchen plumbing technicians walk homeowners through every week. This guide covers how to clean a garbage disposal, how to unclog a garbage disposal that is jammed or draining slowly, and the short list of foods that cause most failures.
Two safety rules first. Always cut power at the wall switch before you reach near the chamber, and never put your fingers inside the disposal. Every step here is done with a tool or from outside the unit.
About Illyrian Plumber
Licensed master plumbers serving Middlesex County, NJ since 2010. We handle kitchen plumbing including garbage disposal installation and repair, faucet and fixture installation, water leak detection, and 24/7 emergency plumbing across East Brunswick, Edison, Sayreville, Old Bridge, Monroe Township, South Brunswick, and North Brunswick.
How to clean a garbage disposal and kill odors
Odor comes from food residue stuck to the grinding chamber and, more often, to the underside of the rubber splash guard. Cleaning both surfaces removes the smell at the source instead of masking it.
Step 1: Grind ice and rock salt
With cold water running, drop in two cups of ice cubes and a half cup of rock salt or coarse kosher salt and run the disposal until the ice is gone. The ice scours hardened food off the blades and the chamber wall, and the salt acts as a mild abrasive. This is the single most effective cleaning step and is safe to do monthly.
Step 2: Deodorize with citrus
Run a handful of lemon, lime, or orange peels through with cold water. The citrus oils leave a clean scent and help cut grease film. Avoid pouring in large amounts of baking soda and vinegar at once. The fizzing looks impressive but does little to remove stuck-on residue compared to the ice and salt method.
Step 3: Scrub the splash guard
With the power off at the wall, lift or fold back the rubber baffle and scrub the underside flaps with an old toothbrush and dish soap. This hidden surface holds the most rot and is the reason a disposal still smells after grinding citrus. Rinse with cold water when done.
Always use cold water, not hot. Cold keeps any fats solid so they grind and flush away instead of melting and coating the pipe downstream.
Disposal beyond a quick fix?
Our licensed plumbers repair and replace garbage disposals across Middlesex County.
How to free a humming or jammed disposal
If the disposal hums but will not spin, the motor has power but the flywheel is stuck on a bone, pit, or piece of cutlery. Shut it off right away. Running a jammed motor for more than a few seconds will trip the overload or burn it out.
Step 1: Cut the power
Switch off the disposal at the wall and, for added safety, unplug it under the sink or flip its breaker. Never reach into the chamber with the power live.
Step 2: Turn the flywheel with the hex key
Most disposals have a hex (Allen) key slot in the center of the underside. Insert the key, which usually clips to the side of the unit, and rotate it firmly back and forth until the flywheel spins freely. This breaks loose whatever is wedged against the impellers.
Step 3: Remove the object and reset
Use tongs or pliers, never your hand, to fish out the jammed object through the drain opening with a flashlight. Then press the red reset button on the bottom of the disposal. Restore power, run cold water, and test in short bursts.
How to unclog a garbage disposal that drains slowly
If the disposal spins fine but water backs up into the sink, the clog is in the drain trap below the unit, not the disposal itself. Chemical drain cleaners are the wrong tool here and can damage the seals. Clearing the trap by hand is faster and safer.
- Turn off the power and place a bucket under the trap to catch standing water.
- Loosen the slip nuts and remove the P-trap, the curved pipe under the disposal. Empty and inspect it for trapped food or grease.
- Check the trap arm and the disposal discharge tube for buildup, and clear them with a bottle brush.
- Reassemble, hand-tightening the slip nuts, then run cold water and check for leaks at each joint.
If water still drains slowly after cleaning the trap, the blockage is farther down the kitchen line. At that point the fix is the same as a stubborn sink clog. Our guide to unclogging a kitchen sink covers the next steps before you call for help.
Garbage disposal repair and replacement
If the unit leaks from the body, trips the reset repeatedly, or no longer powers on, it is usually time to replace it. Our kitchen plumbing team installs and repairs all major disposal brands across Middlesex County.
See our kitchen plumbing servicesWhat never to put down a garbage disposal
Most disposal clogs and jams come down to a handful of foods. Keeping these out of the unit prevents nearly every problem above. According to the US EPA, composting or trashing these items also keeps grease and solids out of the wider sewer system.
Cause clogs in the pipe
- Grease, oil, and fat
- Coffee grounds
- Pasta, rice, and bread
- Eggshells
Jam or wrap the blades
- Celery, corn husks, and onion skins
- Fruit pits and bones
- Potato peels
- Non-food items and cutlery
Run cold water for 15 seconds before and after every use to carry scraps fully down the line. This single habit prevents most of the buildup that leads to odors and slow drains.
When to call a plumber
Call a licensed plumber if the disposal leaks from the housing or the bottom, if it trips the reset button repeatedly, if it will not turn on after a reset, or if water backs up into the sink even after you have cleaned the P-trap. A leak from the body of the unit means a failed internal seal, which is a sign the disposal needs replacement rather than repair.
If the backup affects more than one fixture or you see water pooling under the cabinet, treat it as urgent. Our 24/7 emergency plumbers respond across Middlesex County, and our water leak detection team can trace a hidden under-sink leak before it damages the cabinet or floor.
Frequently asked questions
How do I clean a smelly garbage disposal?
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Grind a tray of ice cubes with a half cup of rock salt to scrape food off the grinding chamber, then drop in a few citrus peels and run cold water for 30 seconds. For odors that linger, scrub under the rubber splash guard with an old toothbrush and dish soap. The splash guard traps the most rot-causing residue and is the part homeowners almost always miss.
Why is my garbage disposal humming but not working?
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A hum with no spinning means the motor has power but the flywheel is jammed. Turn the disposal off, then use the hex (Allen) key that came with the unit in the slot on the underside center to manually rotate the flywheel back and forth until it frees up. Never put your hand in the chamber. Once it turns freely, press the red reset button on the bottom and test it.
Can I use Drano or chemical drain cleaner in a garbage disposal?
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No. Liquid chemical drain cleaners can damage the disposal seals, splash back onto skin, and pool against the blades without clearing the clog. For a clog under the unit, clean the P-trap by hand instead. For grinding-chamber buildup, use ice and salt. If those do not work, a plumber can clear the line safely without corrosive chemicals.
What should never go in a garbage disposal?
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Keep grease, oil, coffee grounds, eggshells, pasta, rice, fibrous vegetables like celery and corn husks, fruit pits, and bones out of the disposal. Grease coats the pipe and hardens, while starchy and fibrous foods wrap the blades or form a paste. These are the most common causes of clogs we see behind kitchen disposals in Middlesex County homes.
Need a plumber for your kitchen?
From garbage disposal repair and replacement to faucet and drain work, our licensed plumbers serve East Brunswick, Edison, and all of Middlesex County, NJ.