PhD: There's More Mold on Windowsills Than Anywhere Else in Your Home — Here, The Best Way to Change That
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PhD: There's More Mold on Windowsills Than Anywhere Else in Your Home — Here, The Best Way to Change That

Jun 24, 2023

Quick: what is one of the dirtiest spots in your home? If you thought the toilet or your garbage can, you’d be incorrect. Turns out, one of the top harborers of dirt are your window sills, and that makes sense: “Sills and window tracks get bombarded with dust, dander and pollen both from outside and inside — plus they have lots of corners and crevices for grime to hide in,” explains Callum Stokes, cleaning expert for House Vacuum Cleaner. “They’re also very common locations for mold to grow, which can impact indoor air quality and really make life tough for people with allergies.”

And you don't need to be allergic to mold in order to have an immune response to it, explains air quality expert Michael Rubino. Simply having a mold sensitivity can trigger symptoms like congestion, sinus pressure, hives, brain fog, chronic tiredness and even infertility. "Over 50 percent of the American population suffers from mold sensitivity,” Rubino shares. “One in four family members in most homes are experiencing adverse health reactions in their own home and don’t even know the cause may be mold." (Click through for more on the adverse health consequences of mold in the home.)

Indeed, there is mold in every home: One study at the University of Arizona in Tucson found that 100 percent of homes harbored mold. Surprisingly, the highest concentrations weren’t found in bathrooms, but near windows. “Window sills provide an entryway for mold spores, and since sills accumulate moisture from condensation, they create a perfect environment for growth,” explains study author Kelly Reynolds, PhD. The good news is, while sills and tracks might be dirt and mold magnets, they’re also relatively easy to keep clean. Read on for easy ways to clean them fast and feel better even faster.

To eliminate spores, clean sills weekly using a solution of ¾ cup chlorine bleach per 1 gallon of water. Or use a disinfectant that contains bleach such as Tilex, which killed mold and neutralized allergens in Reynolds’s research. (Looking to clean your windows while you're at it? Try this genius newspaper trick.)

To get started, just grab these tools:

Your vacuum: Regardless of your window type, simply run the hose attachment along the sill and track to suck out larger or loose dust and debris before you start cleaning.

A toothbrush: This handy tool will help you get into all the nooks and crannies of the tracks, where grime collects.

Your cleaning solution: See below for which one is best based on which type of windowsill or track you want to clean.

Wood is a porous surface, so avoid using water when tackling these sills, since it can soak in and worsen mold issues. Instead, opt for a DIY cleaner like this one from Alex Vargas, manager at Dallas Maids: Mix ½ cup white vinegar, 3 tsp. extra-virgin olive oil and 10 drops of lemon essential oil in a spray bottle.

“The vinegar and lemon are gentle antibacterials that will help remove and prevent future mold growth — and the oil will help moisturize the wood and re-seal it.”

Simply spritz the solution over the sill, then use the toothbrush to quickly scrub any hard-to reach spots in the tracks. Wipe both the track and sill with a clean, dry rag and repeat until it no longer picks up any dirt.

First, look for any spots where the paint may be chipping and give them a good scrub with sandpaper with a grit of 220 or more, which will help dislodge loose areas without scraping away remaining paint. Follow that up with another swipe of your vacuum hose or a damp cloth.

Next, combine 2 cups warm water with 2-3 squirts of dish soap. Use a rag to rub the mixture into the sill and use the toothbrush to scrub it into the track. Rinse with a rag dampened in plain water, then wipe dry with another clean cloth. The dish soap is strong enough to clean dirt but gentle enough not to damage or peel off paint.

If any areas on the paint appear stained, try sprinkling enough baking soda to cover the stain, then rub it with the soapy rag until the spot is lifted.

The most common issue with aluminum window track and sill is they can become discolored or dull over time, typically on the outside due to sun exposure. They can also develop spots, which are caused by the aluminum reacting with the air, resulting in oxidation. The best way to prevent both is with a once-a-month cleaning using this simple method:

Aluminum can be damaged by harsh cleansers like bleach, so it’s best to hit them up with a commercially made aluminum cleaner, such as CLR Metal Clear (Buy from Amazon, $22.56) or California Custom Aluminum Deoxidizer (Buy from Amazon, $18.48) on Amazon for the first round. Simply follow the product directions on the container.

If you notice the sill or track still looks dull or stained after applying the cleaner, just mix a paste of two parts lemon juice to one part baking soda and use a clean sponge to apply it all over the sill, track and frame. Let sit until it dries — usually about 10-15 minutes — then wipe away with a clean, damp rag and your aluminum should be restored to its former shiny self.

These sills typically have what are known as “weep holes” — these allow any water that winds up in the sill due to rain or melting snow to leak back outside and not pool. The only hitch? They also can get clogged, so give them a quick scrub with your toothbrush or use a cotton swab to dislodge any built-up gunk.

Once the grime is gone, plastic and vinyl can easily be cleaned using the same dish soap mixture that works for painted sills. If the surface has stubborn stains, sprinkle on a bit of baking soda and use your toothbrush or a gentle scrubby sponge until it lifts. Finally, to prevent mold and mildew, wipe down the sills and tracks with a cloth dampened in pure white vinegar and let dry. Voila! You’re done!

This video shows how to clean dirt, grime and other gunk from window tracks and sills:

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Lindsay Bosslett is currently associate vice president and managing editor for Health Monitor Network, a patient-education print and digital publishing company. In her role there, she oversees a staff of editors and freelance writers, as well as the production of guides and magazines designed to help both patients and healthcare providers in the ever-changing point-of-care space. As a regular writer for both Woman’s World’s Organized column and First for Women’s Life Smarts page, she delivers practical, creative tips to help women make their lives easier. In her free time, Lindsay enjoys reading, hiking, gardening and attending taco festivals. She lives with her husband, two dogs and lots of bears in a little house on a hill in West Milford, N.J.

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Your vacuum:A toothbrush: Your cleaning solution: For more on the dangers of mold in the home: