How to Clean & Remove Mold from Windowsills

Mildew and mold on windows aren’t just unsightly — they can damage your home and potentially impact the health of sensitive family members and pets. Learning how to effectively clean mold off windowsills, window panes, and window frames is key to maintaining a healthy environment.

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Why clean mold on windows?

Windows are exposed to moisture and temperature changes, which creates an ideal environment for mold and mildew. Common problem areas include window sills, frames, and even spaces between window panes. Mold on windows can also spread to nearby areas, making it essential to tackle it early.

What you need

How to remove mold and mildew from windowsills and frames with bleach

  1. Prep the area

    Remove any window treatments and nearby rugs. Place a towel under the window to protect the floor.

    Tip

    For better ventilation, open a nearby window or use a fan to help circulate fresh air.

  2. Pre-clean the surfaces

    If mold buildup is heavy, start by wiping the area with a wet microfiber cloth to reduce the amount of organic matter. Place the used cloth in the plastic bucket to wash later.

  3. Mix the bleach and water solution

    Wearing safety glasses and gloves, fill the spray bottle with 3 cups of water, then add 3 teaspoons of Clorox® Disinfecting Bleach. Insert the spray nozzle and adjust it to a fine mist.

    Tip

    Make bleach and water solutions fresh each day as they lose potency over time.

  4. Apply the solution

    Hold a cotton washcloth under the area to catch drips, then spray the bleach solution onto the moldy areas. Keep surfaces wet for up to 10 minutes, spraying as needed. Use a microfiber cloth to wipe away mold and an old toothbrush for crevices.

    Tip

    Use multiple cloths, switching out dirty ones as you work to avoid spreading mold spores.

  5. Rinse the window

    Dampen a clean microfiber cloth with fresh water and wipe all treated areas to remove any leftover bleach solution.

  6. Dry the window

    Use a clean, dry microfiber cloth to thoroughly dry the window and prevent moisture buildup.

  7. Wash the cleaning cloths

    After finishing, wash all used microfiber cloths and washcloths on a hot, heavy-duty cycle with laundry detergent and 1/3 cup of Clorox® Disinfecting Bleach.

Never mix bleach with ammonia, vinegar, or other cleaning agents, as this can produce hazardous gases.

How to remove mold and mildew from windowsills and frames with Clean-Up® Cleaner + Bleach

  1. Preclean the area

    For visibly soiled surfaces, preclean before disinfecting.

  2. Spray surfaces

    Hold and spray Clorox® Clean-Up® Cleaner + Bleach 4–6 inches from surface until thoroughly wet.

  3. Wait

    Leave treated surface visibly wet for 5 minutes.

Frequently Asked Questions

Are there alternative cleaning methods for moldy windows?

If you don’t have bleach on hand, you can try these DIY cleaning methods. Use caution, however – if the mold problem is serious, use a specialty disinfecting product or call a professional:

  • White vinegar solution: Spray undiluted white vinegar on moldy areas and let sit for an hour before scrubbing.
  • Hydrogen peroxide spray: Use a 3% hydrogen peroxide solution to kill mold on windowsills. Spray, let sit for 10 minutes, then scrub and rinse.
  • Baking soda paste: Mix baking soda with water to form a paste, apply it to moldy areas, scrub, and rinse.
Are there more tips for cleaning moldy window frames?

Here are some more tips for success.

  • Moldy caulk: If mold is embedded in cracked caulk, consider removing and replacing it, as it’s challenging to clean once mold gets inside.
  • Painting over mold: Don’t paint over mold, as it will eventually bleed through the paint. Always remove mold, then clean and dry the area thoroughly before any painting.
  • Tile and grout care: Regularly clean and reseal tile and grout to maintain a mold-resistant surface.