clean window

How to Clean Mouldy Windows

Before the final inspection, it’s worthwhile getting your tenancy clean completed early to make sure you get your home completely clean. That way, you’re more likely to get your deposit back.

You can either choose to hire a tenancy cleaning company’s professional or do it yourself. Doing it yourself is often more cost-effective, but you have to make sure that all the rooms have been cleaned up to the required standard.

Continous condensation is the primary reason for moulding window sills on your windows. It easily turns into a tenacious problem that even the most composed homeowner/tenant can be thrown into despair. However, given the time-consuming solution which needs some precautions for protection, it is highly effective.

Here’s the way to go about it:

Cleaning supplies you need

The basic things you need for removing mould off window sills are::





Plastic Tarp

Garbage bag

Depending on the amount of mould and the time you’re going to spend cleaning, you might need some more equipment and some safety gear – rubber gloves, a pair of glass goggles and a face mask If the sills are made of wood, you’ll also need:


Dust mask




You can replace the bleach with:

  • Vinegar and ammonia solution;
  • Vinegar and baking soda solution – even though it’s not effective after several minutes, its initial reaction is strong enough to deal with mild mould;
  • Dishwasher soap;

Steps on how to clean window sill mould

1. Equipped with a protection kit–make sure you’re not burning yourself unnecessarily with acidic detergents first. To cover your hands, put on rubber gloves. Should you want to be extra careful, the job will be done by a pair of glass goggles from the convenience store, as well as a face mask for extra protection from mold spores being inhaled. You never know how much mold has formed and how long it has to be scrubbed off.

2. Safe cleaning area–put a plastic tarp or a large garbage bag under the window you’re going to clean to avoid splattering all over the place. Because it can be stable on the surface, the tarp is more suitable, but if you don’t have it, you can also use a garbage bag.

3. Let air in –open the windows and ventilate the spot before you tackle the dirt. Some of the mould spores are going to fall outside this way. Leave it open for the entire cleaning process and then some–this will also evaporate the detergent fumes.

4. Mix your cleaning solution and start scrubbing–even if the mould stains have been quite stubborn and it can damage the window, pure bleach is going to be too heavy. Then, in three parts of lukewarm water, remove one portion of the bleach. In the solution, dip the brush and scrub off the mould. Afterwards, wipe away the scraped particles with the rag.

5. Dry and wipe–take some time to dry out the window sill and scrub off the still hanging mould. Use a cloth, soaked in clean water. Make sure you leave the sill to dry completely before closing the window.

6. Clean the window sill–you have to use sandpaper to clear the last remaining black mould if you wash the mould off a wood. Use your vacuum cleaner to scrub the sawdust. If the wood has been painted beforehand, it will take more time–you will have to prime it and repaint it to restore its original appearance completely.

7. Dispose of the safety gear–remove the plastic tarp, fold it to keep the dust from falling off and put it in a garbage bag.