How do I get rid of black mould in shower grout and silicone for good?

If you have scrubbed the same black line in your shower silicone for months, the exhaustion is real — and it is not because you are doing it wrong. Bleach lightens the stain but leaves the spores, so it grows back. Clove oil takes a different route: its active compound, eugenol, kills mould at the root. A light weekly spray, left 20 minutes, breaks the return cycle.

Why does bleach never seem to fix shower mould?

Because bleach is built to change colour, not to kill what is rooted in porous grout and silicone. Chlorine bleaches the black pigment out of the mould so the stain fades, but the spores underneath survive — and a fortnight later the mould is back in the exact same spot, because it never actually left. That is the cycle: spray, hold your breath, watch it fade, watch it return. It repeats because the product was designed to treat the appearance, not the organism. Understanding that is the first step, because it reframes the problem from “I need to scrub harder” to “I need to kill the thing at the root and then keep it from re-establishing.”

What actually kills mould in grout and silicone?

Clove oil. Its main compound, eugenol, is a documented natural antifungal that disrupts fungal cell membranes and the ergosterol synthesis mould relies on to build them (Pinto et al., 2009, Journal of Medical Microbiology). Sprayed onto grout and silicone and left to sit for around 20 minutes, it kills spores before they can establish, rather than bleaching the surface and leaving them behind. The Clove & Eucalyptus Mould Spray pairs it with pure eucalyptus oil, castile soap, a little methylated spirits to help the surface dry, and water — five ingredients, no chlorine and no caustic soda. This is why the method is leave-on rather than wipe-off: the oil needs contact time to do its work at the root.

Will my silicone look brand new again?

Here is the honest part most brands skip: killing the mould and restoring the look are two different things. Once mould has grown into old silicone, it can leave a permanent stain in the material even after the mould itself is dead. The spray kills mould at the root and stops the cycle of regrowth — that is the real win — but it does not bleach out staining that has soaked into aged silicone, and we will not pretend it does. If your seal is deeply stained, the durable fix for appearance is to kill the mould, keep it from returning, and eventually re-silicone that section. What you are buying is relief from recurrence, not a cosmetic reset. We would rather tell you that up front than sell you a disappointment.

How do I use it, and how often?

Treat it as weekly maintenance, not a one-off rescue. Lightly spray the grout lines and silicone seals, leave it for about 20 minutes so the clove oil can work, and let the surface dry. Done once a week, it kills new spores before they get established, which is what actually breaks the return cycle — the mould stops coming back because you are staying one step ahead of it rather than waiting for the black line to reappear. A 500ml bottle is enough for many weeks of a normal bathroom. This is the opposite of the crisis-scrub approach: small, regular, low-effort, and far less miserable than a monthly battle with bleach fumes.

Is it safe to use in a small bathroom?

It contains no chlorine and no caustic soda, so you are not filling the most enclosed room in the house with bleach fumes. As with any cleaning product, spray in a ventilated space and keep it away from eyes; the methylated spirits that helps the surface dry means it is a clean-with-care product rather than something to breathe deeply. The point of difference from bleach is real — no chlorine gas in a closed shower — but this is general product-use information, not medical advice, and any respiratory concern is a matter for a GP. For which product belongs on which surface, see wall mould vs shower silicone: which product for which job.

Bleach vs Clove & Eucalyptus Mould Spray (grout & silicone)

A fifth-generation eucalyptus maker — making these oils in Australia since 1895 — would rather sell you a weekly maintenance habit that honestly works than a miracle that doesn't. That is why the promise here is recurrence relief, backed by a lifetime money-back guarantee, not a restored-silicone fantasy.

One verified Melbourne customer: “I have tried a lot of mould products in my life, but this has been one of the best. Very effective, easy to use. Follow the directions and to date the mould has not resurfaced.” That is the outcome — it stops coming back.

Frequently asked questions

Does the Clove & Eucalyptus Mould Spray kill mould or just bleach it?
It kills mould at the root — clove oil's eugenol damages the mould's cell membranes — rather than bleaching the colour and leaving the spores.

Will it make my stained silicone look new?
No. It kills the mould and stops it returning, but it does not remove staining that has soaked into old silicone. Badly stained seals may need re-siliconing.

How do I use it?
Lightly spray grout and silicone, leave about 20 minutes, and let it dry. Repeat weekly as maintenance.

Is it safe in a small bathroom?
It has no chlorine or caustic soda, so no bleach fumes. Ventilate and use with care as with any cleaner. This is not medical advice.

Is the clove oil Australian?
No — it is 100% pure clove oil, but clove is not Australian-grown. The eucalyptus oil is the Australian ingredient.

Shop the Clove & Eucalyptus Mould Spray. Related reading: why mould keeps coming back in shower silicone, does clove oil really kill mould at the root, and wall mould vs shower silicone: which product for which job.
References: Pinto E. et al. (2009), Journal of Medical Microbiology, 58: 1454–1462.