How to Clean and Deodorise a Garbage Disposal

The garbage disposal — also called a food waste disposer or InSinkErator — is one of the most useful and most neglected appliances in the kitchen. It grinds food scraps and flushes them through the drain, reducing the amount of food waste going to landfill and keeping solid material out of the drain pipes.

It's also, over time, the source of the persistent bad smell that many people notice coming from the kitchen sink area. The grinding chamber, the splash guard, and the drain walls all accumulate food residue, grease and organic buildup that produce significant odour if not regularly cleaned.

Most people don't know the garbage disposal needs cleaning at all. It's an appliance that you use and forget — until it smells.

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Understanding the Smell Problem

The garbage disposal's grinding chamber processes every food item that goes through it: meat, vegetables, dairy, starchy foods, grease. Even with thorough rinsing, residue accumulates on:

The splash guard: The black rubber flap at the top of the drain opening that you push food through. This is almost always the primary odour source. The underside of the rubber flaps is moist, dark, and receives constant food splatter. Biofilm and mould develop on the underside of the rubber tabs within weeks of installation without regular cleaning.

The grinding chamber walls: The interior walls of the grinder accumulate a thin layer of food residue and grease that builds up over time.

The drain connection: Below the disposal, the connection to the drain pipe can accumulate residue if drainage is slow.

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How Often to Clean

Splash guard: Weekly wipe of the underside of the rubber tabs. This is the highest-impact maintenance task and the one most often forgotten because it requires touching a surface that people prefer not to touch.

Full disposal clean: Monthly, using one of the methods below.

Deodorising: As needed — weekly citrus peel or ice cube treatment takes 30 seconds and significantly controls odour between monthly cleans.

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Step 1: Clean the Splash Guard (Always First)

Safety first: Turn the disposal OFF at the wall switch and unplug it (or turn off the circuit breaker for the disposal) before reaching into or near the drain opening. Never put your hand into a garbage disposal with power connected.

1. Put on rubber gloves.
2. Use your fingers or an old toothbrush to peel back each tab of the rubber splash guard.
3. Wipe the underside of each tab thoroughly with a cloth dampened with dish soap and water. The amount of buildup you find is usually significant — dark, slimy biofilm is common.
4. Clean between the tabs and the inside of the drain opening where the guard sits.
5. Rinse with water.

This single step removes the primary odour source in most disposals. If your disposal smells and you've never cleaned the splash guard underside, do this first — the result is usually immediate and dramatic.

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Step 2: Monthly Full Clean — Three Methods

Method 1: Ice Cubes and Salt (Abrasive Clean)

This method uses the physical action of the ice and salt to scrub the grinding chamber walls and blades.

1. Fill the disposal with a generous amount of ice cubes (a full tray is appropriate).
2. Add half a cup of coarse rock salt or kosher salt.
3. Turn on the cold water.
4. Run the disposal until the ice is completely ground.

The ice acts as a solid abrasive that scrubs the inside of the grinding chamber. The salt adds an additional mild abrasive component and has some antibacterial effect. This physically removes buildup rather than dissolving it.

Method 2: Baking Soda and Vinegar (Chemical Clean and Deodorise)

1. Pour half a cup of baking soda down the drain into the disposal.
2. Follow with half a cup of white vinegar.
3. Allow the fizzing reaction to work for 5–10 minutes — the reaction creates CO₂ bubbles that help loosen residue on the chamber walls.
4. While waiting, clean the splash guard underside as described above.
5. Flush with hot water and run the disposal for 30 seconds.

The vinegar also has mild antibacterial properties and significantly reduces odour. The baking soda neutralises acidic odours from fermented food residue.

Method 3: Dish Soap Deep Clean

1. Plug the drain with a stopper.
2. Fill the sink with warm water and add a generous amount of dish soap.
3. Remove the stopper and run the disposal as the soapy water drains through.

The soap solution cleans the grinding chamber and the upper drain as it passes through. Simple and effective for routine maintenance.

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Deodorising Between Cleans

Citrus Peel Method (Best Option)

The most satisfying and effective ongoing deodoriser:

1. Cut a lemon, lime, or orange peel into small pieces.
2. Run the cold water.
3. Drop the citrus pieces in and run the disposal until ground.

The citrus oils released during grinding coat the disposal chamber walls and drain with a natural, fresh scent. This method also provides mild antibacterial action. Repeat weekly or whenever you have citrus peel available.

Ice and Essential Oil

Drop 10–15 ice cubes into the disposal along with 10 drops of tea tree or lemon essential oil. Run with cold water. The ice abrasion plus the antibacterial and aromatic oil produces a thorough clean and fresh scent.

Specialty Disposal Cleaning Products

Garbage disposal cleaning tablets (InSinkErator's own brand or third-party alternatives) dissolve in the disposal and release cleaning compounds that address biofilm and odour. Use monthly for ongoing maintenance if you prefer a product-based approach.

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What Not to Put in a Garbage Disposal

Understanding what causes problems prevents them:

Avoid:

• Fibrous vegetables (celery, asparagus, artichokes): fibres wrap around the grinder and can jam it
• Starchy foods (potato peels, pasta, rice): these become a paste that coats the chamber and drain
• Grease and cooking oil: solidifies in the drain pipe and accumulates in the chamber
• Bones (particularly fish and chicken): can jam the disposal
• Coffee grounds: fine particles accumulate in the trap and drain
• Eggshells: the membrane on the inside of eggshells wraps around the grinder shaft

Good disposal foods:

• Soft fruit and vegetable scraps
• Citrus (great for cleaning and deodorising)
• Ice (for cleaning the blades)
• Small amounts of cooked food
• Liquid foods and small amounts of food residue

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When the Disposal Smells Despite Cleaning

If the disposal still smells after thorough cleaning including the splash guard:

Check the drain trap: The P-trap (the curved pipe section below the disposal) accumulates food residue and can be a persistent odour source. This can be disassembled, cleaned, and reassembled — or a plumber can do this as part of drain maintenance.

Check for a slow drain: If the disposal drains slowly, food residue sits in the system longer and produces more odour. Slow drainage often means a partial blockage in the drain pipe beyond the disposal — this is a plumbing issue, not a cleaning issue.

Consider the disposal age: Very old disposals develop permanent odour from deeply embedded biofilm that cleaning can't fully address. If the disposal is more than 10 years old and produces persistent odour despite regular cleaning, replacement is worth considering.

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For a professional kitchen deep clean in Adelaide that includes the disposal, drain areas and all kitchen surfaces, contact PF Cleaning Adelaide.

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Written by Victor Jacon — Master Cleaner & Home Detailing Specialist, Founder of PF Cleaning Adelaide.