Short answer: rinse your mouthguard or gum shield in cold water straight after use, clean it with mild soap and a soft brush (not the kitchen sponge), let it air-dry fully before the case goes shut, and soak it properly a few times a week. Never hot water, never the dishwasher: both warp the material permanently.
Your gym bag is not a storage solution, it's an incubator
A mouthguard that goes straight from your mouth into a kit bag, sits there through the drive home, and doesn't come out again until the next training session has basically been given a warm, damp, zero-airflow holiday home. It is not relaxing in there. It is multiplying.
That smell that hits you on day three isn't the mouthguard going off like old fruit. It's bacteria doing exactly what bacteria do when nobody's watching: eating, breeding, and leaving behind exactly the kind of odour that makes teammates edge away from your kit bag.
The routine that actually breaks the cycle
- Rinse in cold water, immediately. Not hot. Hot water is how a mouthguard goes from "fits perfectly" to "fits like it belongs to someone else" in one wash.
- Brush gently with mild soap. A soft toothbrush and a dab of mild soap, not abrasive toothpaste, which can scratch the surface and give bacteria more places to hide.
- Soak it properly, a few times a week. 5 to 20 minutes in a dedicated cleaning solution does what a quick rinse never can: it reaches the surface bacteria builds on, not just what's visible.
- Air-dry fully before storing. A damp guard sealed into a closed case is just a smaller, more portable version of the gym bag problem.
What actually works in that soak
Blakmint's liquid cleaner was tested under ASTM E2315, the lab standard for measuring bacterial reduction on an appliance surface, against a mixed inoculum of four real bacteria strains: Pseudomonas aeruginosa, E coli, Staphylococcus aureus and E hirae. At a 20-minute soak, the result was a 99.99% reduction, printed on the bottle, not rounded up for this page.
It's persulfate free too, which matters more for a mouthguard than most appliances: this is something sitting against your gums and cheek lining for an hour or more at a time during training, not just overnight.
When it's not the cleaning routine's fault
A proper soak-and-brush routine solves the smell and the bacteria. It will not solve:
- A guard that's gone soft or misshapen. Heat damage (hot water, a hot car, direct sun) changes the material permanently; no amount of cleaning reverses a warp.
- Visible tears or thinning. A damaged guard protects less than it looks like it does, and cleaning it well doesn't change that it needs replacing.
- A smell that returns within hours of cleaning. If that keeps happening, the guard itself may have reached the end of its useful life rather than needing a better clean.
Frequently asked
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Can I just use mouthwash instead of a proper cleaner?
Not ideally. The alcohol in most mouthwash can dry out and degrade the material over repeated use, which is the opposite of what you want from something you're trying to make last a season. -
Is it safe to use an ultrasonic cleaner on a gum shield?
Yes, as long as the solution you're using in it is actually stated as ultrasonic-safe. Not every liquid or tablet is, and the label is the only way to know for sure. -
How often should I deep-clean versus just rinse?
Rinse after every single use, but do the full soak 2 to 3 times a week minimum, more often if you're training daily. -
Why does my case smell even when the guard looks clean?
Cases trap moisture just as well as the guard does. Rinse and air-dry the case itself, not just what's inside it.
Done rinsing and hoping for the best? The Blakmint liquid cleaner is £14 for up to 5 months of use, persulfate free, ultrasonic-safe, and works on mouthguards, retainers and dentures alike.
Play a contact sport? Read Mouthguard Cleaner for Athletes for what the clinical research found. For the full appliance range, see Why Liquid Beats Tablets.