The internet is buzzing over One Shot Thick, a concentrated acid toilet bowl cleaner that’s changing the way people tackle bathroom grime.
Though designed for toilets, this cleaner is gaining a devoted following for its surprising ability to tackle messes all around the bathroom.
TikTok user Trace was thrilled with the results, calling One Shot Thick the best thing she’s ever used on shower glass. In her video, she showed how it wiped away eight years’ worth of stubborn build-up in minutes.
Why is everyone obsessed with One Shot Thick?
Initially designed for descaling toilets, One Shot Thick contains sulfamic acid, a heavy-duty ingredient that cuts through hard water scale, calcium buildup, soap scum, and other stubborn stains.
It also has a surprisingly mild scent—a soft floral fragrance rather than the harsh, nose-burning fumes you might expect from a heavy-duty cleaner. Michelle Moore, who works with the company behind One Shot Thick, says it’s about 80 per cent milder in smell than bleach, so you don’t have to hold your breath while you work (though good ventilation is still recommended).
It’s not just for toilets
This hard-working cleaner has earned fans well beyond the toilet. Professional cleaners and TikTok users alike say One Shot Thick makes shower glass sparkle, brings stained sinks back to life, tackles grimy bathtubs, and freshens up most sealed tiles—all without hours of scrubbing.
“It’s one of the few products that actually works.”
Michelle says, “It’s thick enough to cling to vertical surfaces, giving the formula extra time to dissolve deposits and grime.”
She adds, “One Shot Thick removes the scale and stubborn buildup in toilets that a regular brush just can’t shift. This is a common problem that frustrates many people and can be quite embarrassing. It’s one of the few products that actually works.”
“Professional cleaners have started calling it a ‘cleaning hack’ because it also works on shower glass. That’s another spot where grime and hard water deposits build up and feel almost impossible to clean properly.”
Is it safe to use on glass?
Although made for the toilet, Michelle says One Shot Thick is safe to use on glass. Avoid scouring pads, as they can scratch. Instead, use a soft sponge or brush to scrub, then rinse thoroughly and gently.
Can you use it on grout?
Similarly, she says it’s safe to use on grout, but it shouldn’t be left to sit for too long.
“We recommend limiting the contact time on grout to the duration needed for cleaning. Rinse off after use and do not allow the formula to dry on the surface,” says Michelle.
On white unsealed grout, rinse off straight away to avoid blue staining.
What about mould?
You might be tempted to tackle mould with it, but experts advise against this approach.
Michelle says, “We recommend using a specialist mould cleaning product to remove mould because blue staining may occur on unsealed grout.”
How to use One Shot Thick (without ruining your bathroom)
Protect yourself first
Always wear waterproof gloves to protect your skin from the sulfamic acid in the formula. If there’s a chance the cleaner could splash—such as when scrubbing with a bristle brush—put on safety glasses or goggles to protect your eyes. When working in enclosed spaces, such as showers, ensure good ventilation by opening a window or switching on the exhaust fan.
Apply it undiluted
Pour or squeeze One Shot Thick directly onto a soft sponge or brush—never dilute it with water. The product’s thick texture helps it cling to vertical surfaces, such as shower glass or toilet bowls, providing more contact time to break down stubborn deposits.
Scrub gently but thoroughly
Work the product over the surface in small sections, applying light pressure to loosen soap scum, calcium build-up, and limescale. On glass, use a sponge or soft brush to avoid scratches. For tiles and grout, limit the contact time to prevent staining, especially on white unsealed grout.
Rinse with cold water
Once the grime has lifted, rinse the entire surface thoroughly with cold water. This stops the cleaning action, removes residue, and helps prevent streaks. For showers, use the shower head to flush away every trace of the cleaner.
Repeat if necessary
In cases of heavy build-up or older stains, a second application may be needed. For the best results, clean in stages rather than leaving the product on for an extended period
Avoid using on marble, natural stone, unsealed tiles, bare aluminium, corroded chrome, coated aluminium frames, brass, or coloured coated metals.
How often should you use it?
For toilets, you can use One Shot Thick regularly. For showers, it’s best as a deep-cleaning solution whenever you see limescale or stubborn build-up in hard water areas.
Bonus tip to prevent your shower from fogging
After cleaning shower glass or tiles with One Shot Thick, follow up with Clean and Bead from Peerless JAL. It leaves a protective film to slow down the build-up and even prevents fogging.
Where to buy
One Shot Thick is stocked at Bunnings in 1L and 5L bottles. Just be sure to check the website before you dash out, as this sought-after cleaner is flying off the shelves. It can also be purchased on Amazon.
Related stories
Native ad body.
Native ad body.
Native ad body.
