On Wednesday evening, millions of Europeans looked skyward as a total solar eclipse swept across the continent, turning day into dusk from the Iberian Peninsula to the North Atlantic. It was the most dramatic display since 1999, with full totality visible across large parts of Spain and in smaller pockets of Portugal, Greenland, and Iceland.
But the spectacle came with a warning: staring directly at the sun, even for a split second, can cause permanent retinal damage known as solar burn. In the days before the event, shops from Madrid to Reykjavík sold out of certified eclipse glasses, leaving some latecomers to improvise with homemade filters.
Now that the moon has moved on, a new question looms: what happens to the mountains of cardboard and plastic spectacles that were bought for a few minutes of celestial theatre? Environmental groups warn that without proper handling, millions of pairs could end up in landfill.
Can eclipse glasses be recycled?
The short answer is yes, but only partially. The lenses are made from black polymer – a resin mixed with carbon particles that absorb light – or a thin polyester film coated with a microscopic layer of metal. These materials are not accepted by most municipal recycling plants, so the lenses must be removed before the frames can be processed.
Clean cardboard and paper frames can go into your standard paper recycling bin. Plastic frames, however, are a different story – most are not recyclable through kerbside schemes and should be checked with local facilities.
For those who want to avoid the bin altogether, the most sustainable option is to keep the glasses for future use. Modern eclipse glasses that meet the ISO 12312-2 safety standard do not have an expiry date and can last indefinitely, provided they show no signs of wear such as scratches, punctures, or loose filters. Experts generally recommend replacing them after about ten years to be safe.
To test whether your glasses are still safe, hold them up to a bright light. If you see total darkness, the filters are intact. Store them in a protective case or envelope, away from heat and moisture, and they will be ready for the next eclipse.
A golden age of eclipses
The next two years have been dubbed the 'Golden Age of Eclipses' for good reason. On 2 August 2027, a spectacular 'eclipse of the century' will last more than six minutes over Luxor, Egypt. On 22 July 2028, Australia and New Zealand will experience the first total eclipse visible from Sydney since 1857.
If you are not planning to travel to those far-flung destinations, your glasses can still have a second life. Several organisations partner with libraries, museums, and schools to collect lightly used eyewear and distribute them to communities in need around the world. Check local social media groups or community boards for collection points near you.
Alternatively, if you know someone in a country that will experience a future eclipse, consider posting your glasses to them. It is a simple act that keeps waste out of landfill and helps another sky-watcher enjoy the show safely.
For those who missed Wednesday's event, there is some consolation: parts of Europe will see partial phases of the 2027 and 2028 eclipses, and Spain is already gearing up for another major event in 2026. As demand for eclipse glasses surges ahead of each event, the importance of reusing and recycling them only grows.
In the meantime, if you are concerned about your eyes after Wednesday's viewing, know the signs of retinal damage and seek medical advice if you notice any visual disturbances.
And for those already planning ahead, not every part of Spain will see the next total eclipse – so check your location before booking travel.
