Several common household products kill black mold effectively, including white vinegar, hydrogen peroxide, and bleach. The right choice depends on the surface you’re cleaning, since porous materials like drywall and wood require different treatment than tile or glass. For patches smaller than about 10 square feet (roughly a 3-by-3-foot area), you can handle removal yourself. Anything larger warrants professional remediation.
White Vinegar
Undiluted white vinegar with at least 5% acetic acid (the standard concentration sold in grocery stores) kills mold on hard, nonporous surfaces like tile, glass, and sealed countertops. Spray it directly onto the moldy area and let it sit for at least an hour before wiping clean. Vinegar is mildly acidic, which disrupts the cell structure of mold and prevents regrowth on the surface.
The main limitation is penetration. On porous materials like unsealed wood or fabric, mold sends root-like threads (called hyphae) deep below the surface, where vinegar can’t reach. For those materials, vinegar may clear visible mold without fully eliminating what’s growing underneath.
Hydrogen Peroxide
Standard 3% hydrogen peroxide, the kind sold at any pharmacy, is effective against mold on a range of surfaces. It works by breaking down the proteins and DNA that mold cells need to survive. Spray it on, let it sit for about 10 minutes or until the bubbling stops, then wipe the area clean. The bubbling is the peroxide reacting with organic material, which is how you know it’s working.
Hydrogen peroxide has a slight advantage over vinegar in that it also lightens the dark staining mold leaves behind, though it won’t fully bleach surfaces the way chlorine bleach does. It’s a solid middle-ground option: less harsh than bleach, slightly more effective than vinegar on lightly porous surfaces.
Bleach: Effective but Misunderstood
Bleach is the most debated mold killer online, with many sources claiming it only removes surface pigment and can’t kill mold roots on porous materials. The reality is more nuanced. Research from the University of Arizona’s College of Public Health found that household bleach (at standard concentration) reduced more than 99% of mold on drywall surfaces after 10 minutes of contact time. Complete removal was achievable after repeated applications.
So bleach does work on porous surfaces, but it may take more than one round. The practical downside is that bleach produces strong fumes, can damage colored surfaces, and irritates skin and lungs in poorly ventilated spaces. If you use it, dilute about one cup per gallon of water, apply it to the moldy area, and keep it wet for at least 10 minutes. Open windows and wear gloves. Never mix bleach with vinegar or ammonia, as both combinations produce toxic gases.
Borax as a Preventive Measure
Borax (sodium borate) is a naturally occurring alkaline mineral with antifungal properties. It’s less useful as a mold killer and more useful as a mold inhibitor. After you’ve cleaned mold from a hard surface, dissolving borax in water and applying it as a residual coating can help slow regrowth.
Like vinegar and bleach, borax doesn’t penetrate deep enough to eliminate mold embedded in drywall, wood, or fabric. It works best as part of a maintenance routine on surfaces that tend to stay damp, like basement walls or bathroom grout. The key caveat: unless you fix the moisture source, mold will eventually return regardless of what you apply.
How to Clean Without Spreading Spores
Killing mold is only half the job. The other half is removing it without launching spores into the air, where they can settle elsewhere and start new colonies. Mold spores are tiny, generally 10 to 30 microns across, invisible to the naked eye, and easily disturbed by scrubbing or dry wiping.
A HEPA-filtered vacuum is the best tool for initial cleanup. HEPA filters capture 99.97% of particles down to 0.3 microns, which is far smaller than mold spores. Vacuuming the area before and after applying your cleaning solution reduces the number of airborne spores significantly. If you don’t have a HEPA vacuum, wetting the moldy surface before scrubbing helps keep spores from becoming airborne. Use disposable rags rather than sponges, and bag them immediately after use.
Why Moisture Matters More Than the Cleaner
Every product on this list is a temporary fix if the underlying moisture problem persists. Mold needs three things to grow: organic material (wood, drywall, dust), warmth, and moisture. You can’t eliminate the first two from your home, so controlling moisture is the only reliable long-term strategy.
Indoor relative humidity above 70% creates conditions where mold readily colonizes organic surfaces like ceilings, walls, and furniture. The target range for preventing growth is between 30% and 60% relative humidity. A basic hygrometer (available for under $15) lets you monitor this. Dehumidifiers, exhaust fans in bathrooms and kitchens, and fixing leaks at their source are all more important than any cleaning product you spray on a wall.
Condensation on windows, persistent musty smells, and visible water stains are all signs that humidity is too high or water is intruding somewhere. Addressing those issues first means the mold you clean away is far less likely to come back.
When to Call a Professional
The EPA draws the line at about 10 square feet. If your mold patch is smaller than that, DIY removal with the products above is reasonable. If it covers a larger area, or if it resulted from significant water damage (flooding, burst pipes, prolonged roof leaks), professional remediation is the safer route. Large-scale mold removal involves containment barriers and commercial air filtration that prevent spores from contaminating the rest of your home, steps that are difficult to replicate with household equipment.
Mold growing inside wall cavities, HVAC ducts, or behind cabinetry also calls for professional help, since disturbing hidden colonies without proper containment can spread spores throughout your living space faster than any cleaning product can address.