How to clean a washing machine, in one sentence: run a hot, empty cycle with baking soda, then a second hot, empty cycle with vinegar, wipe out the detergent drawer and the pump filter, and give the door seal a pass with a cloth. Do that once a month and the machine that's supposed to be cleaning everything else stops needing an intervention of its own.
We know how that sounds. The appliance whose entire job is "get things clean" also needs to be cleaned — that's not a design flaw, it's just what happens when a metal drum sits full of warm water, detergent residue, and lint several times a week. Here's the full method for every part that actually gets dirty, why the front-load and top-load routines differ, and what that rotten-egg smell is actually trying to tell you.
The short version
Pull the detergent drawer and rinse it, check the pump filter for coins and lint, then run one hot empty cycle with a cup of baking soda in the drum and a second hot empty cycle with two cups of white vinegar — never mix them in the same load. Wipe the seal (and the folds, if you're front-loading) dry afterward and leave the door cracked open. Once a month for most households; every two weeks if you're doing five-plus loads a week or you're in hard-water territory.
In this article
How Often You Actually Need to Do This
Every wash leaves something behind. Detergent doesn't fully rinse away, fabric softener coats the drum in a thin film, and lint and body soil settle into every seam the water can't reach on a normal cycle. Left alone, that buildup becomes a biofilm — a slick coating that bacteria and mold quietly move into, particularly in the door seal and the detergent drawer, where things stay warm and damp between loads.
Once a month is the right cadence for a typical household doing three or four loads a week on a mix of warm and cold cycles. If you're washing daily, running mostly cold loads (which don't rinse residue as well as hot ones), or your water is hard, move to every two weeks. If you've already got a smell, that's not a "someday" problem — that's this weekend.
Here's the opinion part: the "clean it weekly" advice floating around online is overkill for a normal household. Unless you're running six-plus loads a week, monthly is genuinely enough — this is furnace-filter maintenance, not damage control.
The Detergent Drawer and Pump Filter (Where the Grime Actually Lives)
The drum gets the attention. These two parts get ignored, and they're usually where the smell starts.
The detergent drawer. Most drawers slide or pop out entirely — check for a small release tab underneath. Soak it in hot, soapy water for twenty minutes, then scrub the corners and channels with an old toothbrush. That gray-green paste is dried detergent and fabric softener, and it's exactly what feeds mold. Rinse well and air-dry before refitting.
The pump filter. Front-loaders have a small access panel near the bottom, usually behind a flip-down flap. Put a towel underneath first — there's more residual water in there than you'd expect, and it's not clean water. Unscrew the cap slowly, let it drain, then check the filter for coins, buttons, hair ties, and the occasional sock casualty before rinsing and refitting.
(If you've never opened the pump filter before, brace yourself. It's the appliance equivalent of finding out what's actually in the couch cushions.)
How to Clean the Drum — Step by Step
This is the part most guides call "the deep clean," and it's really just two empty hot cycles, run separately.
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1
Empty the machine completely. No clothes, no towels, nothing but the drum itself. This cycle is for the machine, not the laundry.
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2
Add one cup of baking soda directly to the drum. Skip the detergent drawer for this step — baking soda works better against the drum surface directly than diluted through the dispenser.
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3
Run the hottest, longest cycle your machine has. A "Tub Clean" or "Drum Clean" setting if you have one; otherwise the longest hot cycle available. Let it run all the way through, including the spin.
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4
Run a second empty hot cycle with two cups of white vinegar. Pour it into the drum or the detergent dispenser. This cuts through what the baking soda loosened but didn't fully remove — mineral scale, soap film, and the last of the residue.
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5
Wipe down the drum, gasket, and door glass. Once the second cycle finishes, take a clean cloth to the inside of the drum, the seal, and the door. You're mopping up what the cycles loosened before it has a chance to resettle.
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6
Leave the door and drawer open until everything's dry. This one step does more long-term work than either cycle. A closed, damp drum is how you end up back here in three weeks instead of four.
Never combine baking soda, vinegar, and bleach in the same cycle, or use bleach and vinegar back to back without a full rinse between them. Mixing bleach with an acid releases chlorine gas, and it's not worth the risk in an enclosed laundry room. If your machine's manual specifically calls for bleach, run it as its own separate cycle only.
Front Load vs Top Load: What Changes
The two cycles above work for both types. What changes is where the trouble spots are.
Front-loaders have a folded rubber door seal that traps water after every wash — the single most common source of a lingering smell. Pull the fold back, clear out debris, and wipe it dry when you can. If yours has visible black spotting, our step-by-step rubber seal guide covers the deeper clean.
Top-loaders skip the seal problem entirely, but are more prone to waxy detergent buildup on the agitator and under the lid, especially with too much high-efficiency detergent. Wipe both while you're in there for the drum clean.
Everything else — drawer, filter, drum cycles — is identical for both. Only the "one extra thing to watch" changes.
Why It Smells Like Rotten Eggs (and Your Towels Still Smell Musty Too)
A sulfur or rotten-egg smell from a washing machine is almost always bacterial, not mechanical. Washing machines develop their own biofilm — a thin, living layer that forms in the damp, warm, detergent-fed drum and hoses — and certain bacteria in that film produce the same sulfur compounds you'd smell from a neglected drain. Research on household machines has found this biofilm is a normal, expected part of how the appliance ages, not a sign anything's broken.
If your tap water itself smells sulfurous, not just laundry that's been through the machine, that's a water heater or well-water issue — worth ruling out before you blame the washer.
The musty towel problem is the same cause wearing a different hat. Towels hold water longer than anything else you wash, and even slightly damp towels sitting in a machine or hamper give the same bacteria a head start. A clean machine solves half of it; getting wet towels out within the hour solves the other half.
A Faster Way to Keep It Clean Between Deep Cleans
The baking-soda-and-vinegar method above is the deep clean, and it earns its keep once a month. Between those, most of the battle is just not letting residue build back up in the first place.
For the monthly maintenance cycle:
Gentle Sen HOCl tablets dissolve straight into the drum for an empty hot cycle — no measuring vinegar or hunting for baking soda. They're fragrance-free and non-toxic, which matters if your laundry room shares air with a kitchen or a kid's bedroom. Drop one in, run the hottest empty cycle, done.
Our full guide to washing machine cleaning tablets covers how often to use them and where they fall short — they clean the drum, not the seal or the drawer.
Whichever method you use, the habit matters more than the product: wipe the seal dry after the last load, leave the door cracked, and let the drawer breathe. That's most of the battle won before you ever run a cleaning cycle.
Thirty Minutes a Month, Not a Saturday Project
Cleaning a washing machine sounds like a bigger job than it is. Two empty cycles, a rinse of the drawer, a check of the filter, a wipe of the seal — about a load of laundry's worth of time. Do it monthly and the smell, the residue, and the musty-towel question all quietly go away.
Skip it for six months and it's not one bigger clean later — it's the same clean, against a machine that's had longer to build the habit you now have to break.
See the Gentle Sen HOCl Tablets →Frequently Asked Questions
How often should I clean my washing machine?
Once a month for a typical household doing three to four loads a week. Move to every two weeks if you're washing daily, running mostly cold cycles, or dealing with hard water. If you already notice a smell or visible residue on clothes, clean it now rather than waiting for the next scheduled date.
Why does my washing machine smell like rotten eggs?
It's almost always bacterial. Washing machines develop a biofilm inside the drum and hoses from residual detergent, water, and warmth, and certain bacteria in that film produce sulfur compounds — the same smell you'd get from a neglected drain. A monthly hot empty cycle with baking soda and vinegar breaks the buildup down. If your tap water itself smells sulfurous, that's a separate water heater or well-water issue, not the machine.
Can I use vinegar and baking soda together in one cycle?
You can, but two separate cycles clean better. Baking soda works best applied directly to the drum surface; vinegar works best rinsing through afterward. Combined in one wash, most of the reaction happens in the water rather than against the buildup you're trying to remove. Running them as two consecutive empty cycles gets more actual cleaning done.
Is it safe to use bleach in my washing machine?
In moderation, on its own cycle, most manufacturers allow it. What's not safe is combining bleach with vinegar or any acidic cleaner — that releases chlorine gas. Bleach is also harder on rubber seals and gaskets over repeated use than vinegar is. We default to vinegar and baking soda for that reason, and treat bleach as an occasional, standalone option rather than a routine one.
Why do my towels still smell musty even after washing?
Towels hold more water than almost anything else you wash, which gives bacteria a head start if they sit even slightly damp — in the machine after the cycle ends, or in a hamper before the wash. A clean machine removes one source of the smell; getting damp towels out of the drum and into the dryer promptly removes the other. Both matter.
What's different about cleaning a front load vs top load washing machine?
The core drum-cleaning routine — baking soda cycle, then vinegar cycle — is the same for both. Front-loaders have a folded rubber door seal that traps water and needs regular wiping since that's the most common source of odor. Top-loaders don't have that seal, but can develop waxy detergent buildup around the agitator and under the lid instead.
How do I clean the washing machine pump filter?
Locate the small access panel near the bottom front of the machine, place a towel or tray underneath to catch residual water, and slowly unscrew the filter cap. Let it drain fully, pull the filter out, and clear any coins, lint, or debris. Rinse it, confirm the small pump wheel behind it spins freely, then screw everything back into place. Check it every month or two, more often if you regularly wash items with loose debris like pet bedding.
Do washing machine cleaning tablets work as well as vinegar and baking soda?
For the drum itself, yes — both work by running through a hot empty cycle to break down residue and buildup. Tablets are faster since it's one cycle instead of two, and there's no measuring involved. Neither method cleans the detergent drawer, pump filter, or door seal on its own — those still need a manual wipe-down regardless of which drum method you use.
Sources
- Bacterial Exchange in Household Washing Machines — National Institutes of Health (PMC)
- A Brief Guide to Mold, Moisture and Your Home — U.S. Environmental Protection Agency
- Laundry Care Guide — American Cleaning Institute
This article is for informational purposes only and does not constitute professional appliance-repair or cleaning advice. Gentle Sen products are general-purpose cleaners and are not intended to diagnose, treat, or prevent any condition.
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