How to Clean a Front-Loading Washing Machine
I get called out to “broken” washing machines about twice a month and nine times out of ten the machine isn’t broken at all. The door seal has been quietly hosting a colony of black biofilm for two years, and the owner has finally noticed that their towels smell like a damp basement no matter what detergent they use. Last month I scraped 187 grams of black sludge out of one Bosch Serie 6 — weighed it on the kitchen scales out of curiosity. The owner had been running her machine on cold every single wash for four years. Right, gear first — and a quick word on chemistry, because the dishwasher-tablet hack you’ve seen on TikTok doesn’t actually work. It cleans the drum, sure, but leaves the seal, the detergent drawer, the sump filter and the rubber gasket folds completely untouched. That’s where 95% of the colony lives.
Gear you’ll need
- Sodium percarbonate (OxyClean or Bunnings own brand, $12 for 1kg) — NOT chlorine bleach
- White vinegar — 2L from Coles
- An old toothbrush and a microfibre cloth
- A small bucket and rubber gloves
- A torch (the seal folds are dark)
- Cotton buds for the detergent drawer corners
- A flathead screwdriver for the sump filter cover
- Old towels — there will be water on the floor
Step 1: Pull the detergent drawer all the way out
On Bosch and Samsung there’s a small tab inside the drawer — push it down and the whole drawer slides free. Miele uses a release button at the back. If you’ve never taken yours out, brace yourself: the underside is usually black, slimy, and smells like a public bin in February. This is normal and it is genuinely gross. Soak the drawer in hot water with two scoops of sodium percarbonate for 30 minutes. Skip the fancy spray, just use percarbonate — and don’t substitute bleach, it’ll perish the rubber drawer seals inside a year.
Step 2: Clean the drawer cavity
With the drawer out, shine the torch into the cavity. You’ll see the underside of the dispenser arm caked in detergent residue and mould — gravity means most of the gunk sits up there. Mix one cup of vinegar with one cup of warm water and scrub the cavity with the toothbrush. Here’s the science: detergent residue is alkaline and traps moisture; vinegar is acidic and dissolves the residue while breaking the biofilm matrix. Pay attention to the roof of the cavity — that’s where alot of people miss.
Step 3: Fold back every door seal pleat
This is the bit everyone skips. The rubber gasket has 3-4 internal folds, and water pools in each one after every wash. Gloves on. Pull each fold open, wipe with a microfibre dampened in vinegar, inspect with the torch. You’ll find hair, coins, lint, dead spiders, and that one missing AirPod tip from 2024. I’m not exaggerating about any of those. Don’t use bleach on the seal — it’ll perish the rubber inside 12 months and a replacement gasket is $180 plus a service call. Vinegar and elbow grease only. Dwell time is everything here too — let the vinegar sit on the seal for 5 minutes between fold-wipes.
Step 4: Open the sump filter
Bottom-front of the machine, behind a small panel — pop it open with the flathead. Old towel down first. There’s always 200-500ml of stagnant water in there. Unscrew the filter (anti-clockwise), pull it out, clean off the fluff and coins. On a five-year-old machine I usually find about $3.40 in change. Rinse the filter under hot water, scrub the threads with the toothbrush, and screw it back firmly — finger tight plus a quarter turn. Over-tighten and you’ll crack the housing.
Step 5: Run the 90°C maintenance wash
Empty drum. Pour one cup of sodium percarbonate directly into the drum (not the drawer). Set the machine to its hottest cotton cycle — 90°C on Bosch and Miele, “Sanitise” on Samsung, “Whites Plus” on Westinghouse. No pre-rinse. Run it. Here’s the science: 90°C denatures the biofilm proteins (the structural matrix that holds the mould colony together), and the percarbonate releases hydrogen peroxide which oxidises what’s left. One single hot cycle does more than twelve vinegar washes. After this you’ve got a genuinely sterile drum.
Step 6: Run a vinegar rinse cycle
Once the hot cycle finishes, pour 500ml of white vinegar into the drum and run a short cold rinse. This neutralises any percarbonate residue and descales the heating element. Aussie water hardness varies hugely — Sydney (Warragamba) is soft, Melbourne is among the softest in any major city, Brisbane is moderate, but Adelaide and Perth are properly hard and benefit most from the monthly vinegar. The element is the thing that goes first when scale builds up; vinegar maintenance doubles its life.
Step 7: Wipe the door glass and seal dry
Microfibre, dry the inside of the door glass, dry every seal fold one more time. Reinstall the cleaned detergent drawer. From now on, leave the door ajar after every wash — this is the single biggest behaviour change you can make. A closed door traps residual moisture, the drum sits at 25-35°C between washes, and that’s the perfect mould nursery. Door open = drum dries = no colony.
Step 8: Lock in the monthly habit
Set a recurring calendar reminder for the first Saturday of every month. The full routine takes 15 minutes of hands-on time plus a 2-hour wash cycle running unattended. If you skip a month you’ll know — the next towel load tells you. I do it on the same day I clean the dishwasher filter because both jobs live in the same headspace and take a single Saturday morning.
Step 9: Switch one wash a fortnight to 60°C
Even between maintenance washes, alternate your sheets and towels between cold and 60°C. Cold-only washing is what got you here. Modern detergents (Cold Power, OMO Sensitive, Earth Choice) are formulated for cold but they don’t kill bacteria or denature biofilm — only heat does that. The Aussie reality: most front-loaders sold here are cold-fill only (no hot inlet), so the machine has to heat internally via the element. If the element is scaled (back to step 6), it can’t reach 60°C and your “hot” wash is actually warm. Vinegar maintenance keeps the element working.
Step 10: Check the standpipe and hoses annually
Once a year, pull the machine out from the wall and check the drain hose for kinks and the standpipe for blockages. A partially blocked drain leaves dirty water sitting in the sump between washes — that’s a separate mould source most people never address. Same time, eyeball the inlet hoses for any sign of bulging or weeping at the joins. Inlet hoses are a $25 replacement at Bunnings and a 10-minute job; ignoring a weeping one is how kitchens get flooded at 2am.
When you should NOT DIY this
If your machine has standing water that won’t drain even after clearing the sump filter, that’s a pump failure or a blocked drain pipe deeper in the system — that’s a service callout, not a cleaning job. Same if the drum spins unevenly, the bearings rumble, or it walks across the laundry on spin cycle. Heavy mould growing on the plasterboard wall behind the machine (not just on the seal) is a moisture-source problem under AS 3740 — the machine isn’t the issue, the room ventilation or a leak behind the wall is. And don’t try to replace the gasket yourself if it’s perished — the procedure varies wildly by brand and a wrong refit floods the laundry.
Common screw-ups
- Using bleach on the rubber seal — perishes it within 12 months and a replacement gasket is $180 plus labour.
- Skipping the seal folds — that’s where 95% of the biofilm lives, no amount of drum-cleaning fixes it.
- Closing the door after a wash — traps humidity, regrows the colony in days.
- Cold-only washing forever — modern cold detergents don’t kill bacteria, you need a 60°C cycle in the rotation.
- Adding fabric softener thinking it’ll fix the smell — softener actually feeds the biofilm and makes the problem worse.
Cost & time
Materials: about $20 for a kilo of percarbonate, a bottle of vinegar, microfibres and cotton buds if you don’t have them. The percarbonate lasts about a year of monthly use. Time: 15 minutes hands-on plus an unattended 2-hour wash cycle. Compared to a $220 service callout for “the machine smells”, this pays for itself ten times over.
If your towels smell like wet dog within 24 hours of washing, your machine is the problem, not your detergent. No amount of fabric softener will fix a contaminated drum — softener actively feeds the biofilm. Strip the seal, run the 90°C cycle, leave the door open. Three steps, monthly, forever. Your nose will thank you and so will your $1,400 machine. While the machine is pulled out for the annual hose check, check whether it needs to refill faster — slow-fill is almost always a partially-blocked inlet filter, a 5-minute fix. Caddy out, let’s go.
