To clean a garbage disposal, turn it off and cut the power, scrub the underside of the rubber splash guard and the top rim of the grinding chamber, then fill the sink halfway with warm water, stir in 1/4 cup of baking soda, and pull the plug as you switch the disposal on. Do it monthly, or whenever it smells.
That's the method InSinkErator gives in its guide to garbage disposal odors. InSinkErator's first cleaning step is the underside of the splash guard, the black rubber flaps in the sink opening (it calls this the baffle). Food smears on it every time you push scraps through, it never gets rinsed properly, and it grows a gray-black film. Grinding lemons or pouring vinegar down the drain won't remove it.
Why does my garbage disposal smell?#
InSinkErator says a smelly disposal is usually a sign of food buildup from not running enough water. A quick burst of the tap while the motor runs isn't enough to carry the ground food down the drain, so some of it sits in the chamber and the pipe below.
Other places the smell comes from:
- Slime under the splash guard.
- Food left in the chamber because the disposal was switched off too soon.
- A partial clog in the drain line further down.
- Grease that went down the drain, solidified, and trapped food.
How to clean a garbage disposal, step by step#
- Switch the disposal off and cut the power. Unplug it under the sink if it plugs in, or switch off its breaker. The wall switch alone isn't enough, because someone can flip it back on.
- Never put your hand into the disposal, even with the power off. InSinkErator says it on its support pages, and it means tongs or pliers for anything you need to fish out.
- Look at the splash guard. On some models it lifts straight out; if yours does, scrub both sides with a brush and hot soapy water. If it's fixed, fold the flaps up with a long-handled dish brush or a scouring pad and scrub the underside and the rim of the chamber below it.
- Shine a flashlight down. If anything's in there (a bottle cap, a fruit sticker cluster, a twist tie), lift it out with tongs or pliers.
- Put the stopper in and fill the sink halfway with warm water. Stir in 1/4 cup of baking soda.
- Restore power. Turn the disposal on and pull the stopper at the same moment. The rush of water flushes the chamber and the drain behind it.
- Let cold water run for a few more seconds after the sink empties.
If you have a double sink, block the other drain while you do the flush, or the water takes the easy route out.
Hot or cold water in a garbage disposal?#
Cold, while it's grinding. InSinkErator's instructions for using a disposal say to run a steady stream of cool water before you switch it on, keep it running while it grinds, and let it run for a few seconds after you switch off to flush the pipe. It says draining hot water through it between grinding sessions is fine.
Turn the disposal on before you add food, and feed scraps in gradually. A big handful all at once slows the grinding and leaves more behind.
What can't go in a garbage disposal?#
Fats, oils, and grease. InSinkErator says never, for every model it makes. They coat the pipes, harden, and catch everything that comes after.
The rest depends on your model, and the usual warnings don't all apply. InSinkErator's list of what each of its models can grind includes coffee grounds, eggshells, pasta, rice, and citrus rinds for its standard models. Bones, celery, and corn cobs are only listed for its heavier-duty Advanced Series. If you have an older or smaller unit, keep the fibrous and hard stuff in the bin or compost.
Non-food items never go down: twist ties, rubber bands, glass, paper towels.
Do lemons or vinegar clean a garbage disposal?#
Not really. InSinkErator lists citrus rinds as fine to grind on all its models, and they leave a fresh smell for a while. But neither lemon nor vinegar reaches the film under the splash guard, which is where so much of the smell lives. Use them as a finish after the scrub, not instead of it.
Skip chemical drain cleaners unless your disposal's manual says they're allowed. If the clog doesn't clear, you're left with a sink full of caustic water that you, or a plumber, then have to deal with.
Garbage disposal humming but not working#
A hum with no grinding usually means something's jammed. InSinkErator's jam fix goes like this:
- Switch it off and cut the power.
- Check inside with a flashlight and remove anything stuck with tongs or pliers.
- Under the sink, find the small hex-shaped hole on the bottom of the unit. Fit the wrench that came with it, or a standard 1/4-inch Allen key, and work it back and forth until it turns freely in full circles.
- Find the small red reset button on the bottom. If it has popped out, press it gently. If it won't stay in, wait ten minutes and try again.
- Restore power and run cold water before switching it on.
Don't keep flicking the switch while it hums. It just strains a motor that can't turn.
When to call a plumber#
Water dripping from the body of the unit, a smell like sewage rather than old food, or a sink that drains slowly even with the disposal off all point past the disposal. Start with our kitchen sink drain guide, and call a plumber if that doesn't clear it. A disposal that keeps tripping its reset button after you've cleared the jam needs service too.
If your dishwasher drains through the disposal, a clogged disposal can also leave water standing in the dishwasher. Our dishwasher guide covers that side.
A scrub-and-flush once a month keeps the smell from coming back. Pairing it with taking out the kitchen trash, or a recurring reminder in ChoreLists.com, makes it stick.