How to get stubborn black mold off exterior brick
Standard scrubbing and degreasers fail on deep-set exterior black marks because the growth embeds into the material rather than sitting on the surface. Trying to force it with hard-bristled brushes often strips the surrounding mortar instead of removing the stain, leaving homeowners stuck between ruining the masonry or resorting to painting over it.
What the numbers show
Counted from the threads quoted below. How we count
- This comes up 14.4× more often in r/homeowners than across the site as a whole.
What people tried
Every workaround mentioned in the threads below. We haven’t tested any of them — and nobody here is claiming they worked.
Found another way around this?
Share your steps and trade-offs so fellow engineers don't have to reinvent the wheel. No account required.
- 1Pressure washing2 people mentionedDid this help you?
- 2Using a hard bristled brush with a degreaserDid this help you?
- 3Painting over the brick and mortarDid this help you?
- 4Ignoring the marks entirelyDid this help you?
- 5Hiring an expert to clean it with hypo and correct PPEDid this help you?
- 6Painting over the stained metalDid this help you?
- 7using a power washer with RainX Shower Glass CleanerDid this help you?
- 8Using bleachDid this help you?
- 9Using vinegarDid this help you?
- 10Using mineral spiritsDid this help you?
- 11Using iron or rust stain removers for concreteDid this help you?
- 12Using CLRDid this help you?
- 13Using muriatic acidDid this help you?
- 14Pressure washing with a less aggressive nozzleDid this help you?
- 15Having a licensed arborist treat the tree in the springDid this help you?
- 16Using Dawn dish soap or a degreaserDid this help you?
- 17Scrubbing kitty litter into the spot with a shoe, sweeping it up, rinsing with a hose, and repeating if oil reappearsDid this help you?
- 18Using car shampooDid this help you?
- 19Using rubbing alcoholDid this help you?
- 20Using adhesive removerDid this help you?
- 21ScrapingDid this help you?
- 22Considering outdoor porcelain tile over the surfacesDid this help you?
- 23Sand blasting or media blastingDid this help you?
In their words
Unedited, grouped by where they were said, most upvoted first within each place, each linked to the thread it came from.
“How do I get the rest of these oil stains out of my brave new driveway?”source ↗
“I used an overnight oil eater and it worked well and removed most of the stain but left behind a faint dark spot.”source ↗
“The faint stains become more obvious when the driveway is wet.”source ↗
“What are my options? How can I make it look better? Is there a concrete stain I can use to hide the stain that actually works?”source ↗
“I tried a hard bristled brush and degreaser which worryingly had more impact on the mortar than the brick.”source ↗
“Can the black marks be cleaned or is it a characteristic of the brick?”source ↗
“I tried everything to remove this stain from my car door but it won't budge. Don't want to have to get it repainted.”source ↗
“No idea. I tried car shampoo and rubbing alcohol but neither worked.”source ↗
“We are going to a Lowe's tomorrow and are looking for suggestions on what to buy to put in the containers to help get the stubborn Grime off (we are lazy and haven't washed the house in the 6 1/2 years we have owned it).”source ↗
“What is the best way to fix this? It’s like a black mold that is not able to be scrubbed off and has permanently stained the metal?”source ↗
“The mold is embedded into the metal , it won’t scrub off”source ↗
“Looks like the kind of mold that gets deep into the paint, scrubbing won't do much at this point”source ↗
“Yep exactly right. I’m thinking my only option is to like paint over it? Just unsure the best solution or what products to use for this”source ↗
“The patio is under an elm tree. Is there any way to clean this? We tried soap and oxy clean but it doesn’t work that well.”source ↗
“Coastal AL Lawn care service came out and applied 8.9 gallons of SEA 90 and this was left behind. I've tried bleach, vinegar, mineral spirits, pressure washing, nothing is making a dent.”source ↗
“If I get any on my sidewalk or driveway, EVEN ONE GRAIN, I get a rust stain.”source ↗
“I'm thinking the same thing. I've contacted the lawn care company to see if they will take care of this for me. My security cameras show that their truck was parked right where the stain pooled up.”source ↗
Where this came up
People with this problem also raised
- 24How to get oil stains out of concrete without a power washer
- 2Best way to fill holes in concrete before painting
- 2How to remove a persistent drip mark from a garage door?
- 22How to clean dirty stone tiles without ruining them
- 24How to get dried mucus off painted walls without ruining the paint
- 46How to get dried paint stripper off hardwood floors