How to Clean Moldy Window Sills and Frames
Condensation can be a serious problem in winters with low temperatures. Moist and warm air inside the house can harbour devastating mould in the most unpredictable areas, such as on window sills and frames.
The worst part is that mould spores can lead to various health hazards, including respiratory disorders or even cause damage to your window frames and other components.
So, it becomes your responsibility to address potential issues, such as leaky pipes, leaky roof gutters, condensation accumulation, inadequate ventilation, malfunctioning HVAC systems, etc., and treat the mould stains as quickly as possible. This becomes more imperative if you are at the end of your tenancy period.
Here is a comprehensive guide to cleaning mouldy window sills and frames using proven methods. Make sure you wear protective gear and open the windows for the best possible results.
Let’s Get Started!
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]1. Arrange Necessary Cleaning Supplies
Begin the process by stocking up on necessary cleaning tools and products. Since you are doing it yourself, avoid using store-bought products as they contain harsh chemicals.
Instead, prepare eco-friendly stain removal recipes using organic ingredients. So, here is the list of items you will need to combat mould spores:
- Microfiber cloths
- Nylon scrub brush or an old toothbrush
- Rubber gloves
- Vinegar
- Hydrogen peroxide
- Baking Soda
- Tea Tree Oil
- Warm Water
- Dishwashing Liquid
Note: Make sure you wear a face mask, especially if you are an asthma or allergy sufferer.
2. Dry off the Window Frame And Sills
If the window sill and frame are wet, dry them off. Grab a dry microfiber cloth or towel to absorb excess moisture. Wear gloves and a mask before starting the process to prevent the worsening of allergy symptoms.
Do not touch mould spores at this stage. Just remove the excess water. This will help you clean windows more effectively.
You can also hire professionals for an expert end of lease cleaning Canberra. They can help you clean dirt-laden windows, doors, cabinets, kitchen, bathrooms, and other surfaces with perfection. With their assistance, you can get your full bond back.
3. Spray White Vinegar on Mouldy Areas

White vinegar contains 5-8 per cent acetic acid, which can effectively kill and remove mould spores from almost any surface. According to experts, undiluted white vinegar can kill around 80 per cent of common household mould types, including black ones.
All you need to do is to:
- Pour around 1 cup of undiluted white vinegar into a spray bottle.
- Spray the solution on mouldy window sills and frames. Let the mould saturate completely.
- Leave it for an hour. This will allow the vinegar to break down the fungi and make it easy to scrub the stains.
- Next, scrub the area gently with a brush. It is good to use an old toothbrush to reach the tight spaces within the sills.
- Spray warm water and wipe down the area.
- Let it dry completely.
Make sure you resolve common household problems and prepare your property for the final rental inspection.
4. Use 3 % Hydrogen Peroxide For Stubborn Mould Stains
Believe it or not! Hydrogen Peroxide is one of the most effective mould removers when you want an eco-friendly solution. If you don’t have vinegar, use this powerful alternative, especially for window frames.
It can kill visible mould without damaging the wooden structure of your windows. It penetrates delicate surfaces to remove mould spores and make your work much easier.
According to end of lease cleaning Canberra Professionals, mix equal portion of 3 per cent hydrogen peroxide and water to the window sill and frame.
Let it sit for 40 minutes, and wipe it off with a clean cloth.
5. Spray Tea Tree Oil For Best Results
Tea Tree oil is a natural and effective option when it comes to tackling mould and other harmful germs. It has antibacterial properties that can make your task easier.
The best part is that it can prevent mould from the roots and stop them from growing back. Mix 10 drops of tea tree oil in warm, soapy water. Shake it well and spray the solution on the sills and frames.
Tip: Make sure you de-clutter and clean basement to prevent mould infestation.
6. Gently Scrub using Baking Soda
You can also use the power of baking soda to get rid of mould from your window sills and frames. This natural cleaning agent works well when use the power to scrub the stains.
Add a teaspoon of baking soda with two cups of water and spray it on the mould. Now, gently scrub with a nylon brush or an old toothbrush.
Rinse, wipe, and air dry completely.
7. Prevent and Control Mould Infestation
Prevention is always better than cure. So, here are some great ways to prevent the mould growth on window sills and frames:
- Remove Excess Moisture: Use a dehumidifier in winter to reduce condensation during winter and stay safe at home.
- Remove Dirt and Grime: Regularly vacuum your window sill or wipe down your frames to get rid of loose dirt, dust and hair.
- Apply mould-resistant Paint: Use mould-resistant paint on window frames to prevent mould growth.
If you are at the end of your tenancy, book experts for a budget end of lease cleaning Canberra and save your hard-earned bond money.
A Guide to Cleaning Mouldy Window Sills & Frames

Wrapping Up
Window sills and frames are the most overlooked parts of a home. However, they can harbour disease-causing mould, which can damage your windows and pollute the indoor air. So, follow these simple ways to clean mouldy windows like a pro and ensure a clean and healthy abode.