Washing up liquid, hand sanitiser, the corner of your clothes... it's tempting to reach for the nearest item when your glasses need a quick clean, but what if you've unknowingly been damaging them with every wipe?
We spoke to expert optometrist Daniel Hardiman-McCartney, clinical adviser to the College of Optometrists.
He gave us his advice on the do's and don'ts when it comes to cleaning your glasses and sunglasses, so you can keep them in good condition and avoid shopping for replacements prematurely.
Read on to find out how not to clean your glasses, and the best two methods we would recommend.
A drop of washing up liquid and warm water is one of the most commonly used methods for cleaning glasses, and it's also one of the most destructive.
With repeated use the grease-busting chemicals in washing up liquid, known as surfactants, will craze the lens coating on your glasses.
That means a web of fine cracks will appear on the surface of your lenses, especially in the middle, resulting in glare and slight reductions in your vision through your glasses.
Daniel says, 'Eventually people will be able to spot that crazing damage on the surface of your lenses, but from afar it'll just look like your glasses are dirty.'
Thanks to Covid-19 a bottle of hand sanitiser is rarely out of reach, but you should stick to using it on your hands, not your glasses.
Alcohol is an aggressive chemical which with repeated use will erode both the lens coatings and the frames of your glasses.
Hand sanitisers with an alcohol content of 60% or more are recommended for use by the World Health Organisation (WHO), so it's likely that any hand sanitisers you use on your hands will be harmful to your glasses.
Window and glass cleaner sprays are the go-to for cleaning glass and mirrored surfaces around your home, so why not the glass that you wear?
The ingredients in household cleaners aren't designed with reading glasses and sunglasses in mind, and they're as damaging as they are ineffective at cleaning them.
'Household glass cleaners tend to smear when used to clean spectacles, and some of the chemical ingredients will also wear away the varnish on your frames, so they're not recommended,' advises Daniel.
'It might sound rather obvious, but if you're using a spray of any kind you must also remember to take your glasses off first. I've seen plenty of people who've hurt themselves because they forgot to take their glasses off before spraying them.'
Sometimes it can be all too tempting to just give your glasses a scrub with a bit of your t-shirt, but it should be avoided if you can help it.
'You could be rubbing dirt - which may not always be visible to the naked eye - into your glasses. This will not only fail to clean your glasses properly but could add lots of tiny scratches to the surface of your lenses, too,' according to Daniel.
Some clothing materials, especially wool, are just too abrasive for cleaning glasses. Even if the clothes are clean they could still scratch the surface of the lenses.
Though putting some on your thumb might be an effective way to clean food off your child's face, saliva is not recommended as a substitute glasses cleaner.
Some people, according to Daniel, even put contact lenses in their mouth to clean them before putting them back into their eyes.
Putting saliva close to or in your eyes puts you at much greater risk of corneal (front part of your eye) infections. Save yourself the risk and don't use saliva to clean your specs.
Rinsing your glasses is recommended as it helps to remove bits of dirt and grit that could otherwise scratch your lenses, but if the water is too hot it will also cause damage.
'Lukewarm water is kinder to your glasses than hot water,' says Daniel.
'They're delicate and aren't designed to cope with high temperatures. Boiling water will be especially damaging.'
Liquid or hand soap is fine for carefully cleaning stubborn dirt or oil from the frames of your glasses, but are best avoided for cleaning the lenses.
This is because plenty of shop-bought soaps contain similar surfactants to those present in washing up liquid, and it's difficult to tell which ones contain them. Best to play it safe and steer clear altogether.
If you do want to clean your frames using soap, make a lather with the soap in your hands and apply that to the frames before rinsing them off with lukewarm water and drying them carefully afterwards.
'Since the pandemic began I've been asked on several occasions if I advise buying a UVC light sanitising machine for glasses, and I often see them advertised on social media', says Daniel.
'While there are some studies that say UVC light can be effective at viral cleaning, the College of Optometrists and the Scottish Government conducted an evidence review on this topic and weren't convinced.
'Even if UVC light is an effective sanitiser for your glasses, it won't remove any grease or dirt from them, so they're still limited in their usefulness.'
UVC light is also dangerous - exposure can cause damage to your eyes and skin.
Lint fibres are little magnets for dirt and dust, so if you use lint-based tissues to clean your glasses you'll likely rub those bits onto your lenses, scratching them and leaving dust particles behind.
However, if they're lint-free - and in the case of baby wipes, alcohol-free - they should be fine to use.
'The packaging doesn't make it obvious what is truly lint-free so it can be difficult to tell, but most household kitchen rolls are lint-free so that's probably your best bet,' according to Daniel.
'This is the best option,' advises Daniel. 'Most optometrists will supply you with a bottle of lens cleaner and a microfibre cloth when you first get your glasses, so most people start off with the best option to hand already.'
Alcohol-free liquid lens cleaners are gentle on the delicate lens coatings of glasses, and the microfibre cloth removes grease and smears without the risk of scratching, making this the optimum choice for keeping your glasses clean and free from damage.
'The trick with this method that often catches people out is using the same microfibre cloth for several years. It'll get dirty or gritty eventually, and people will then scratch their glasses when they rub the cloth on their lenses.
'The cloths are cheap or sometimes free to replace, but the most sustainable route is to buy a microfibre cloth that's machine-washable.'
There's currently no standardised labelling for machine-washable microfibre cloths, so it's best to ask the manufacturer, retailer or seller first before you buy them.
A lot of optometrists also offer free refills of the cleaning liquid, which can help to reduce the cost of cleaning your glasses.
There's a huge variety of single-use microfibre lens wipes that are purpose-built for cleaning glasses, and they can be very effective at doing it.
However shopping for them can be a minefield. Many cannot be recycled, so where possible buy compostable wipes with recyclable packaging to reduce your impact on the environment.
Some wipes are also alcohol-based and are advertised for use on your phone or laptop screen as well, but the alcohol in those wipes is too aggressive for your glasses and will end up causing damage.
'They're also quite expensive as there's an ongoing cost for them,' says Daniel. 'When used sparingly, however, they are handy for scenarios such as travelling, where it's more convenient to have something you won't have to keep with you once you've used it.'