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How to clean and remove mouldy silicone

A shower with a glass door in a bathroom with tiles on the walls.

Overview

Mould can cause serious health issues, and it also looks unsightly. Getting rid of mould from shower silicone and other areas of your bathroom is easier than you might think. With the right supplies and information from this step-by-step guide, you’ll have fresh, clean silicone in no time.

Safety tip: Always wear the appropriate safety equipment (safety glasses, gloves, ear muffs and a mask, for example) and always follow the instructions for the product or equipment.

Steps

1Clean the surface

It’s important to wear the proper safety equipment (gloves and a mask, for example) to prevent inhaling any mould spores. Ensure the room has proper ventilation by opening a window or using the exhaust fan. Use a microfibre cloth to clean surfaces – you want a dust-free, debris-free, and hair-free environment.
A hand wearing green gloves is wiping the surface with a microfibre cloth.

2Remove the silicone

Use a rubber or plastic scraper to gently scrape away the silicone. Be careful not to damage the surface.
Green Bunnings hammer
Tip: Holding the blade at a low angle will help avoid damage.
A hand wearing green gloves is using a scraper to remove silicone.

3Wipe the surface

After removing the bulk of the silicone, clean the area with mineral turpentine or isopropyl alcohol to eliminate any residue. Allow it to dry in preparation for the silicone remover.
A hand in green gloves is cleaning the surface with a cloth, and there is silicone residue scattered on the floor.

4Apply the silicone remover

To remove any remaining silicone, use a silicone caulk remover or a specific silicone sealant softener. Apply the product according to the manufacturer's instructions with a scraper, allowing it to soften the silicone for around two hours. Once the time is up, use a rag to wipe off the remover and any excess silicone.
A hand wearing green gloves is using a Trojan paint scraper to apply silicone caulk remover

5Clean the surface

Once you’ve wiped down the area, wipe it down again with methylated spirits to ensure the area is clean and free of any silicone debris or cleaning residue. Allow to dry for a few minutes.
A person holding diggers methylated spirits in one hand and cloth in the other hand.

6Apply a mould remover

Carefully examine the area where the silicone was removed for any signs of mould or mildew. These may appear as dark spots, discoloration, or a fuzzy growth. Mix a solution of water and mould or mildew cleaner according to the product's instructions. Spray the mildew remover on the affected area and allow it to sit according to the instructions on the label. Once this is done, wipe the solution away with a damp cloth.
Green Bunnings hammer
Tip: If you’re after a more natural approach, or if you’ve got a milder mould problem, you can use a mixture of one-part bicarb soda to two-parts white vinegar, which is effective at killing mould.
A person with green gloves is spraying Selleys mould killer onto the affected surface.

7Wipe the surface

Give the area another wipe down with mineral turpentine and allow it to dry. This will prepare the area for a new layer of silicone.
A hand in green gloves is wiping the surface with a cloth.

8Lay masking tape

If you want to achieve a neat and precise finish, use masking or painter's tape to seal off the areas adjacent to where you plan to apply the silicone. This helps in creating clean lines and it makes clean-up easier.
A person is applying masking tape with one hand and pressing it down with the other to secure it in place.

9Apply the new silicone

Now it’s time to apply the new silicone. Using a sharp utility knife, cut the tip of the silicone tube at a 45-degree angle. The size of the opening should match the width of the gap you intend to fill. Use the built-in seal puncture tool found on the silicone tube's cap or use a separate tool to break the seal inside the nozzle.

Insert the silicone tube into a caulking gun. Squeeze the trigger repeatedly until the silicone starts to emerge from the nozzle. Hold the caulking gun at a 45-degree angle and, with a steady hand, apply a smooth, even bead of silicone along the intended gap or seam. Keep a consistent pace to maintain a uniform appearance.

A hand wearing green gloves is applying fresh silicone between the masking tape.

10Smooth the silicone

Before the silicone dries, spray some soapy water and use a smoother or your finger to smooth down the silicone. Wet your finger with the soapy water or use the scraper to gently run it over the freshly applied silicone to smooth out any imperfections and create a clean finish. Allow the silicone to cure for 72 hours or according to the label.
Green Bunnings hammer
Tip: If you’ve used masking tape, carefully remove it while the silicone is still wet. This helps achieve a clean, defined edge.
A hand in green gloves is using a scraper to smooth out freshly applied silicone.

11Clean the area

Wipe up any silicone spills or clean up the edges with a rag and mineral turpentine.
A person is carefully peeling off masking tape from the surface.

12Preventative measures

To reduce the chances of future mould, regularly clean the area, keep the space well-ventilated and use your exhaust fan in high-moisture areas.
A nice and white sparkling silicone in a tiled shower.
Health & Safety

Please make sure you use all equipment appropriately and safely when following the advice in these D.I.Y. videos. You need to be familiar with how to use equipment safely and follow the instructions that came with the equipment. If you are unsure, you may feel it is safest to consult an expert, such as the manufacturer or an expert Bunnings Team Member.

Grave health hazards are linked to asbestos, which may be in homes built up to 1990. Health hazards may result from exposure to lead-based paints in older materials and copper chromium arsenic (CCA) treated timber. For information on the dangers of asbestos, lead-based paint and CCA treated timber and tips for dealing with these materials contact your local council's Environmental Health Officer.