Mould on a Front-Load Washer Gasket: How to Remove the Black Stains
Black spots that stay on a front-load washer's rubber seal after a wipe are mould stains, fed by water and detergent residue trapped in the fold. Dry the seal, run a line of a bleach gel such as BLITZ Mold Stain Remover on the stains, leave it 3 to 5 hours, then wipe and rinse. The thick gel stays on the stain for hours, where a diluted bleach wipe gets 5 minutes.
Shop BLITZ Mold Stain Remover, $24.95
In this guide
Why black mould forms on a washer gasket
The fold of the door seal holds a little water after every load, plus lint and the detergent and softener that didn't rinse away. Damp residue in the dark is what mould grows on, and over weeks it tints the rubber. The usual causes:
- The door stays shut between loads. LG says moisture then can't dry and mould may form inside the gasket.
- Water left in the fold and wet laundry left in the drum. LG's manual says to wipe the seal after each cycle and take items out right away.
- Too much detergent or softener. Samsung Canada says the buildup can contribute to odours.
- Cold-only washes. Samsung Canada lists frequent cold-only washing as a common cause of odours.
Surface stain or set-in? Check before you start
First, wipe the fold with warm, soapy water. Grey film and slime that come off are residue: the routine in our front-load washer gasket cleaning guide handles them. Black dots that stay are stains in the rubber surface, and scrubbing harder won't lift them.
How to remove mould from a washer seal, step by step
You need: BLITZ Mold Stain Remover, rubber gloves, eye protection, two cloths and a dry towel. Time: about 15 minutes of work, plus 3 to 5 hours while the gel sits.
- Clean the drum first, if you're doing it. Run one BLITZ Washing Machine Cleaner tablet in the empty drum on a hot cycle (on a Samsung, a regular hot cycle, not Self Clean), then let the washer drain. Never run the gel and a tablet at the same time.
- Wipe out the fold. Pull the rubber back, remove lint and coins, and wipe with warm, soapy water. Tried vinegar already? Rinse it off with clean water.
- Dry it completely. The gel goes on a dry surface so it sticks.
- Gear up and air out. Gloves, eye protection, and a window open or the fan on: the gel can irritate skin and eyes.
- Run a line of gel on each stain. Shake the bottle, then lay the gel right on the black, inside the fold and along the bottom.
- Leave it 3 to 5 hours, door open. Keep kids and pets away.
- Wipe, rinse, dry. Wipe the gel off with a damp cloth, rinse the seal with clean water two or three times, and dry it. We suggest an empty Rinse and Spin before the next load.
Careful: BLITZ Mold Stain Remover is a chlorine bleach gel (sodium hypochlorite and sodium hydroxide). Never use it with another cleaner, vinegar or ammonia: Health Canada warns that bleach reacts with ammonia or acids, including vinegar, and releases toxic gases. If you're exposed, call your provincial poison centre (in Québec, 1-800-463-5060).
What to expect: results vary with how deep the stain goes, and old, deep stains may need a second round. On the product page, 95% of surveyed customers "noticed lighter mould and mildew stains after the first treatment" (survey of 60 BLITZ customers, 2026; results are self-reported).
Shop BLITZ Mold Stain Remover, $24.95
Can you use bleach on a washer gasket? Diluted wipe or gel
Yes. LG's manual, Samsung's WF6000T manual and Whirlpool all give the same mix: 3/4 cup (177 mL) of liquid chlorine bleach in 1 gallon (3.8 L) of water, with rubber gloves. Samsung and Whirlpool say to leave it 5 minutes, then wipe and dry. LG's help page also offers oxygen bleach in warm water. Every brand's full routine is in the gasket guide's maker section.
The gel's difference is time on the stain: a diluted wipe gets 5 minutes, the gel stays put on the sides of the fold for hours. A bleach spray fits rubber worst, since the Tilex label says to rinse rubber right away. The full comparison is in gel vs bleach spray for black caulk and washer seals.
| Diluted bleach wipe (makers' method) | BLITZ Mold Stain Remover gel | |
|---|---|---|
| Time on the stain | 5 minutes, then wipe and dry | 3 to 5 hours, then wipe and rinse |
| On the sides of the seal | Runs down into the fold | Thick: stays where you put it |
| Shop the gel, $24.95 |
When the stain is permanent, and when to replace the gasket
If a stain hasn't changed after two rounds (our rule of thumb), it's set into the rubber and another product won't lift it either.
- Soft, whole seal, faded stain: it's cosmetic. Keep the seal dry, or replace it if it bothers you.
- Torn, cracked or hard rubber: replace it. A tear at the bottom can leak on every load.
- Loose or deformed seal: Electrolux says to unplug the washer, close the water tap and contact an authorized service centre.
LG's help page notes that a technician's visit to clean the gasket is a paid call, since gasket cleaning isn't a product fault. Ordering and fitting tips are in the gasket guide's replacement section.
Keep the stains from coming back
- After the last load: take the laundry out, towel-dry the bottom of the fold, and leave the door and drawer ajar (LG, Samsung). With small children or pets, close the laundry room door instead.
- Every week: wipe inside the fold, as Samsung Canada recommends.
- Every wash: HE detergent at the label dose, easy on softener, and a warm wash now and then when care labels allow.
- Every two weeks: one BLITZ tablet in the empty drum on a hot cycle: 24 tablets last a year.
Seal clean but the washer still smells? See what a cleaning cycle misses.
Black spots on your laundry
- Read the care label. An empty triangle means any bleach, a triangle with two lines means non-chlorine bleach only, and a crossed-out triangle means no bleach.
- Rewash in the warmest water the label allows, once the seal and drum are clean. Old stains may stay on some fabrics.
- Never put the gel on fabric. It's not made for fabric or delicate materials.
Why BLITZ Mold Stain Remover for a washer seal
- A gel that stays put on the sides of the seal for 3 to 5 hours, then wipes off.
- Listed for this job: washer gaskets, fridge and dishwasher seals, caulk and grout. One 236 mL bottle, $24.95.
- Rated 4.7 out of 5 (13 reviews) on goblitzclean.com.
- A Québec company based in Laval, with service in French and English. Septic-safe. Free shipping in Canada from $40 ($7.95 below), most orders in 2 to 3 business days, 10% back in store credit and a 30-day money-back guarantee. Also on Amazon.ca.
Frequently asked questions
Can I use bleach on my washer's rubber seal?
Yes. LG, Samsung and Whirlpool give a diluted wipe: 3/4 cup of liquid chlorine bleach per gallon of water, left 5 minutes. For black stains that stay, a thick bleach gel such as BLITZ Mold Stain Remover sits on the stain for 3 to 5 hours instead. Wear gloves, and never mix bleach with vinegar, ammonia or another cleaner.
Can I use BLITZ Mold Stain Remover on an LG washer gasket?
Yes. BLITZ lists front-load washer gaskets among the gel's uses, whatever the brand. Dry the seal, run a line of gel on the stains only, leave it 3 to 5 hours, then wipe and rinse the seal two or three times.
Should I run the cleaning cycle before or after the gel?
Before. Run the tablet cycle first, let the washer drain, then apply the gel. Never use the gel and a tablet, or any other cleaner, at the same time.
Does vinegar remove mould stains from a washer gasket?
No. Vinegar isn't a bleach, so it doesn't lighten black stains. If you've used it on the seal, rinse it off and let it dry before any bleach product.
Sources: BLITZ Mold Stain Remover product page; LG WM4000H owner's manual and LG help library; Samsung Canada support page and WF6000T owner's manual; Whirlpool and Electrolux support pages; the Tilex label on clorox.ca; Health Canada; Innovation, Science and Economic Development Canada (care symbols). Checked October 20, 2026. LG, Samsung, Whirlpool, Electrolux and Tilex are trademarks of their owners. BLITZ is not affiliated with them.
LIFT THE BLACK STAINS
BLITZ Mold Stain Remover
A thick bleach gel that stays on washer seals, caulk and grout and lifts black and pink stains from the surface. Dry the surface, run a line of gel, leave 3 to 5 hours, wipe off and rinse. 236 mL, $24.95.
CLEANING THE DRUM TOO?
BLITZ Essentials Kit
Washing Machine Cleaner and Dishwasher Cleaner, 24 tablets each: about a year of both at one tablet every two weeks. $43.95, $4.95 less than buying them separately. Run the washer tablet first, let it drain, then use the gel.
