How I scored free solar eclipse glasses -- and checked if they're safe

If you plan on enjoying April's total solar eclipse, whether you're already living in the path of totality, making the trip to be there, or planning on enjoying a partial eclipse somewhere else, you're going to need protection. We've covered all the basics you need to know about the upcoming total solar eclipse, and built a guide for finding the best eclipse glasses you can purchase online, but building your own pinhole viewer isn't the only way to watch the eclipse safely for free.

Thousands of libraries across the US are distributing solar eclipse glasses for free, and all you have to do is ask a friendly librarian to get one — no membership required. A free pair might not be as fancy as some of the options available for purchase online, but with the total solar eclipse only days away, not having to deal with shipping is the best option anyway. But how good are free solar eclipse glasses, and how do you know if they're safe? I grabbed a pair of my own to find out.

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Library freebies

The solar eclipse glasses my local library stocked were shipped flat and have to be folded into shape to use. If you've ever worn red-blue 3D glasses — before 3D TVs and the Vision Pro, one of the simplest ways to watch 3D movies at home — you have a good idea how these solar eclipse glasses feel and work. The key difference is they have dark gray metallic lenses rather than translucent red and blue ones, and are completely opaque unless you're looking directly at the sun.

My pair has branding from the US National Science Foundation and illustrated Sun and Moon on the outside and directions and safety certification information on the inside, but otherwise looks the same as the dozens of other solar eclipse glasses from their manufacturer American Paper Optics (who also, coincidentally, makes 3D glasses). More importantly, for my future eclipse viewing experience, though, they easily fit over my glasses.

The glasses aren't the most comfortable option out there, and certainly not the most durable, but for the