Since proper hygiene is crucial to fighting the spread of COVID-19, hand sanitiser has become one of the most sought-after items in the country. It's so in-demand that it might be tough finding supplies in nearby stores and even online. At this point, you may be eyeing that 4-year-old bottle you forgot you had in your bathroom cabinet. At least it will suffice when you're out on an important grocery run, right?

Not so fast.

"Expired hand sanitiser is safe to use, but it's unknown how effective it is," says Dr. Robert Rountree, a preventative medicine specialist.

Hand sanitiser has an expiration date for a reason. The active ingredient in most hand sanitisers is alcohol, which can evaporate over time. An effective batch of hand sanitiser, according to the Centres for Disease Control and Prevention (CDC), contains at least 60% alcohol. But after you open the bottle, the alcohol content will slowly begin to diminish as it continues to be exposed to air. Most hand sanitisers will last up to three years after their manufacture date.

If your stash is low, you might think about making your own bottled solution or disinfecting wipes by mixing rubbing alcohol and aloe vera. But this process can be messy and frustrating. If you try pouring straight alcohol on your hands, you can dry out your skin, weakening its defensive barrier and increasing your risk of infection.

It's important to emphasise that people who have access to clean water don't have to jump through these hoops to keep germ-free. Rinsing your hands with good old soap and water for at least 20 seconds is the best way to kill coronavirus.

Hand sanitiser should only be used a backup for when you don't have access to a sink and hand soap—like when you are grabbing groceries or running another important errand. If you're out and about and all you have is that expired Germ-X in your handbag, use it.

"It's better to use some alcohol than none if you have no other option," says Dr. Rountree.

So think twice before you toss out that neglected container of hand sanitiser, especially if it's unopened. Nowadays, it could be at least a bit useful when you are in a real bind.

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