How to Clean a Washing Machine (Front-Loader and Top-Loader)

Why a Washing Machine Needs Cleaning at All

It seems backwards that a machine full of soap and hot water would get dirty, but it does. Every wash leaves behind a film of detergent residue, fabric softener, body oils, and lint in places the water never fully flushes: the rubber door gasket, the detergent drawer, the drum’s outer tub, and the drain hose. That film stays damp between loads, and damp organic residue is exactly what mold and odor-causing bacteria need. The result is the classic musty smell that transfers to clean towels, plus grey flakes appearing on dark clothes.

Most machines need a full clean every one to three months, more often if you wash in cold water, use liquid detergent or fabric softener heavily, or keep the door shut between loads.

What You Need

• White vinegar (about 2 cups) or a commercial washing machine cleaner tablet
• Baking soda (½ cup)
• Old toothbrush and a few microfiber cloths
• A bucket and shallow tray (for the drain filter)
• Rubber gloves

Skip bleach if your machine’s manual advises against it, and never mix bleach with vinegar. The combination releases chlorine gas.

Cleaning a Front-Loading Washer

Front-loaders are the more odor-prone design because they seal tightly and hold a small pool of water behind the door gasket.

1. Clean the door gasket first. Pull back the rubber folds and wipe out the trapped hair, lint, coins, and black mildew spots with a cloth dipped in a 1:1 vinegar-and-water solution. Use the toothbrush along the seam. This is where most of the smell lives; skipping it means the rest of the clean is wasted effort.

2. Empty the drain pump filter. Almost every front-loader has a small access panel at the bottom front. Lay a towel down, put a shallow tray underneath, open the cap slowly and let the water drain. Expect anything from a cup to a litre. Unscrew the filter, pull out the sludge and debris, rinse it under the tap, and screw it back in firmly. A clogged filter causes slow draining and standing water.

3. Wash the detergent drawer. Most pull out entirely if you press the release tab. Soak it in hot water for ten minutes, then scrub the dispenser slots and the cavity it sits in with the toothbrush. Softener compartments in particular collect a thick gel.

4. Run a cleaning cycle. Pour 2 cups of white vinegar into the drum (not the detergent drawer) or drop in a cleaner tablet, then run the hottest, longest cycle your machine offers, or the dedicated “tub clean”/“drum clean” cycle if it has one. Run it empty.

5. Second cycle with baking soda (optional but effective). Sprinkle ½ cup of baking soda into the drum and run a short hot cycle to neutralise remaining odor and rinse loosened residue away.

6. Dry everything. Wipe the drum, gasket, and glass dry, then leave the door and detergent drawer ajar.

Cleaning a Top-Loading Washer

1. Fill and soak. Set the machine to the hottest, largest, longest cycle. Let the tub fill completely, then add 3–4 cups of white vinegar. Let the agitator run a minute to mix, then pause the cycle and let it sit for one hour.

2. Scrub while it soaks. Use that hour to wipe the lid, rim, dispenser cups, and the outside of the agitator with vinegar solution. The underside of the lid and the rim groove are usually the grimiest spots.

3. Resume and repeat. Let the cycle finish and drain. Then run a second full hot cycle with 1 cup of baking soda to rinse away everything the vinegar loosened.

4. High-efficiency top-loaders (no central agitator, low water) should be treated more like a front-loader: use a tub-clean cycle and a cleaner tablet, since they won’t fill deep enough for a proper soak.

Why It Works

Detergent residue and hard-water minerals form an alkaline, slightly waxy scale on plastic and metal surfaces. Vinegar’s acetic acid dissolves the calcium and magnesium in that scale and lowers the pH enough to break the film’s grip, letting hot water carry it out the drain. Baking soda works differently: it’s mildly abrasive and alkaline, so it neutralises acidic odor compounds produced by bacteria and helps lift greasy body-oil deposits. Heat matters more than either: many biofilms only break down reliably above roughly 60 °C, which is why cold-wash-only households get musty machines fastest.

Common Mistakes

• Cleaning the drum but ignoring the gasket and filter. These two spots hold the actual mold colony. A vinegar cycle just circulates water past them.
• Using too much detergent long-term. Overdosing is the single biggest cause of buildup: excess suds don’t rinse out and leave a residue layer that feeds bacteria. HE machines need roughly a tablespoon or two, not a full cap.
• Mixing vinegar and bleach, or vinegar and baking soda in the same cycle. The first is dangerous; the second just neutralises both into salty water, wasting the cleaning power. Use them in separate cycles.
• Using vinegar constantly on a machine with rubber components. Occasional use is fine, but a weekly vinegar cycle can prematurely degrade rubber hoses and seals on some machines. Once every one to three months is plenty.
• Shutting the door immediately after unloading. A sealed damp drum is a mold incubator. Leave it ajar for a few hours.

When Cleaning Won’t Fix It

If the musty smell returns within a week of a thorough clean, the problem is likely deeper than the drum. Biofilm can build up in the outer tub (the plastic shell you can’t see or reach), in the drain hose, or in the sump. A repeat cycle with an enzyme-based or oxygen-bleach machine cleaner over two or three consecutive weeks sometimes clears it.

Call a technician if you see standing water after cleaning the filter, if the smell is sewer-like rather than musty (that suggests a drain or trap venting problem in your plumbing, not the machine), or if you notice black flakes even after repeated cleans. That can mean the outer tub needs dismantling. A leaking gasket with visible cracks should be replaced rather than scrubbed.

FAQ

Can I use bleach instead of vinegar? Yes, if your manual permits it: 1 cup of liquid chlorine bleach in the drum on a hot empty cycle kills mold effectively. Always run a second rinse cycle afterwards so residual bleach doesn’t damage the next load of clothes, and never combine it with vinegar or ammonia-based cleaners.

Why do my clothes smell worse after washing? This usually means bacteria in the machine are transferring onto fabric, or you’re overloading so clothes never rinse properly. Clean the machine fully, cut your detergent dose, and wash towels at 60 °C to reset them. Leaving wet laundry in the drum for hours also re-contaminates it.

Does fabric softener damage the machine? It doesn’t damage components, but it’s a leading cause of buildup: softeners are oil- and wax-based and coat the dispenser, hoses, and drum with a sticky film that traps lint and bacteria. If you use it, clean the dispenser monthly, or switch to white vinegar in the rinse compartment as a softening alternative.

How do I stop mold from coming back on the gasket? Wipe the gasket dry after your last load of the day, remove trapped items from the folds weekly, and leave the door open. If black spots persist in the rubber itself, they may be permanently stained rather than live mold. As long as the surface wipes clean and doesn’t smell, staining is cosmetic.