How to Clean an Automatic Washing Machine? | Remove Sludge & Odors Fast

Cleaning an automatic washing machine requires a monthly hot-water cycle with vinegar, baking soda, bleach, or a commercial tablet, plus manual scrubbing of the gasket, filter, and detergent drawer.

A washing machine that smells like mildew or leaves gray sludge on your socks isn’t broken — it’s dirty. The fix is a monthly hot-water cycle using common household cleaners or a name-brand tablet, followed by a few minutes of hand-scrubbing where grime hides. Whether you own a front-load Samsung or a top-load Whirlpool, the same rules apply: remove buildup from the drum, gasket, drain filter, and detergent dispenser. This guide covers every method straight from manufacturer documentation, so you can pick the one that fits what you have in the pantry.

Why Your Machine Builds Up Sludge In The First Place

Gunk and odors come from trapped detergent scum, fabric softener residue, hard-water minerals, and bacteria that thrive in warm, damp environments. Front-load washers are especially prone because their sealed rubber gasket stays wet between loads. Top-load machines accumulate debris under the agitator and in the tub rim.

Running a cleaning cycle once a month prevents the buildup from reaching the point where it transfers back onto your clothes. If you wait until you smell it, the gasket folds already harbor a visible layer of mold.

What You Need To Clean A Washing Machine

Most of these items are already under your kitchen sink. For the commercial tablet route, you will want Affresh or Glisten tablets — both cost roughly $10 to $15 per pack.

• Cleaning agents: white vinegar, baking soda, chlorine bleach (unscented), hydrogen peroxide, or a commercial washer tablet (Affresh, Glisten, Tide)
• Tools: microfiber cloth, soft-bristle brush (toothbrush), sponge, spray bottle, warm soapy water
• Safety gear: rubber gloves (optional, recommended when handling bleach)

Method 1: Front-Load Washer With Vinegar & Baking Soda

This gentle but effective combination handles routine gasket grime, detergent residue, and mild mustiness. It is safe for all front-load brands including LG, Samsung, Whirlpool, and GE.

1. Set the washer to the hottest, longest cycle — look for “Clean Washer,” “Basket Clean,” or “Heavy Duty”.
2. Add 2 cups of white vinegar to the detergent tray or directly into the drum.
3. Add ¼ cup of baking soda directly into the drum.
4. Start the cycle and let it run completely.
5. Once the cycle finishes, wipe the inside of the door, the drum, and the exterior with a damp sponge. Pay special attention to the rubber gasket — pull the folds back and scrub away any black or brown buildup.
6. Dry all surfaces thoroughly with a clean, dry cloth. Leave the door open for at least an hour afterward to air out.

The drum will feel smoother to the touch, and the musty smell should be gone or significantly reduced.

How To Clean A Top-Load Machine Without An Agitator

Top-load washers (both agitator and impeller models) collect residue around the top rim, under the lid, and inside the outer tub. The following two-step bleach-and-vinegar method is the standard from manufacturer guides — but do not mix bleach and vinegar in the same cycle. That creates toxic chlorine gas. Run them separately.

1. Set the washer to the hottest, longest cycle with the largest load size setting.
2. Add 4 cups of liquid chlorine bleach to the bleach dispenser or drum. Let the machine fill, then pause or stop the cycle and let the water soak for 1 hour.
3. Restart the cycle and let it finish completely.
4. Run a second cycle — again on the hottest, longest setting — and add 4 cups of white vinegar. Let it fill, stop the cycle, and soak for another 1 hour.
5. Restart and complete the wash cycle.
6. Dip a sponge into the remaining vinegar water and scrub the detergent basket, agitator (if present), and tub lip before drying everything with a clean cloth.

The water at the end of the first soak will appear gray or sudsy — that is dissolved residue exiting the machine.

Method 2: Commercial Tablet — The Easiest Route

Whirlpool, Speed Queen, and GE all recommend Affresh tablets for their machines. This method requires zero measuring and works on front-load and top-load washers.

1. Remove all clothing from the basket.
2. Place 1 Affresh tablet directly at the bottom of the drum — never in the detergent dispenser.
3. Select the “Clean Washer” or “Basket Clean” cycle. If your machine lacks that option, use the hottest, longest cycle.
4. Run the full cycle. Do not pause or interrupt it.
5. After completion, leave the door or lid open for ventilation until the interior is fully dry.

The tablet should dissolve entirely within the first few minutes of the cycle.

If you prefer to use household bleach instead of a tablet, pour 1 cup of liquid chlorine bleach into the bleach dispenser, select “Clean Washer,” and hold START/PAUSE for three seconds.

Where Sludge Hides: Gasket, Filter & Drawer Deep Clean

A machine can smell fresh after a hot cycle but still harbor gunk in three places that only a manual scrub reaches. These steps matter — especially the gasket, where Frigidaire’s official guide warns a hidden layer of mold can breed within the folds if you never pull them back.

The Gasket (Front-Load Only)

1. Unplug the washer for safety, especially if you will be working near the front panel.
2. Spray the entire door seal with warm soapy water or a 50/50 vinegar-water mix.
3. Pull back every fold of the rubber gasket and scrub the hidden surfaces with a soft brush or toothbrush.
4. Wipe away the loosened debris with a damp cloth.
5. Dry the gasket completely with a clean towel. Use a soft brush to avoid tearing the rubber seal.

The Drain Filter

1. Unplug the washer. Locate the small access panel on the lower front of the machine.
2. Open the panel, then unscrew the filter dial slowly — water will drain out, so place a shallow pan or towel underneath.
3. Remove the filter, scrub it with a brush and warm soapy water, and pick out any lint or debris.
4. Reinsert the filter, close the panel, and plug the machine back in.

The Detergent Drawer

1. Pull the drawer out completely. Many models have a release tab on the back — press it to remove the drawer entirely.
2. Separate any removable inserts and soak everything in warm soapy water for 10 minutes.
3. Scrub away residue with a small brush, rinse, and wipe dry.
4. Reinsert the drawer and run a short rinse cycle to clear the detergent housing.

Common Mistakes That Waste Your Time

A few avoidable errors stop a cleaning cycle from working — or worse, damage the machine.

• Overusing bleach: More than 1 cup of chlorine bleach per cycle can corrode seals and plastic components over time.
• Interrupting the cleaning cycle: Pausing the cycle mid-run means the solution never soaks long enough to dissolve residue. If interrupted, restart the full cycle.
• Putting the tablet in the dispenser: The tablet belongs at the bottom of the drum — the dispenser’s flow is too slow to dissolve it effectively.
• Skipping the gasket: A hot cycle alone cannot reach inside the gasket folds. Manual scrubbing is mandatory for front-load machines.
• Adding detergent: Detergent neutralizes the cleaning chemistry. The drum must be empty of all laundry and detergent.

What About Naturally Hard Water?

If you live in an area with hard water (white deposits on faucets), mineral scale builds up faster inside the washer. Borax or washing soda mixed in equal parts works well when your machine lacks a dedicated “sanitize” or “clean washer” cycle. Simply add ½ cup of each to the drum and run a hot cycle. For already-heavily scaled machines, a commercial cleaner like Affresh is more effective than vinegar alone.

Finish With The Routine That Keeps It Clean

1. Run one cleaning cycle per month using the method that matches your machine and water type.
2. Scrub the gasket and detergent drawer immediately after the cleaning cycle, while the rubber is still damp and pliable.
3. Check the drain filter every three months — especially if your machine leaves small lint deposits on clothing.
4. Leave the door open between washes for at least an hour to let internal moisture evaporate. This single habit cuts the gasket-mold problem by roughly 80%.
5. If your machine’s odors return within two weeks, repeat the deep-clean procedure and check for standing water in the drain filter housing.

If you are shopping for a new automatic washer and want one built with easier maintenance in mind, check out our roundup of top-rated models — we tested each one for cleaning performance and real-world convenience: best automatic clothes washers reviewed.