What to Do With Leftover Solar Eclipse Glasses

If you’ve thought about saving your solar eclipse glasses until the next eclipse, it’s not a bad idea. The American Astronomical Society says modern eclipse glasses do not expire. If the glasses were compliant with the ISO 12312-2, and have no punctures, scratches or tears, and the filters/lenses remain attached to the frames, they will last.

Older eclipse glasses used materials that degraded over time, so they were often printed with a 3-year expiration period. That is no longer true. One manufacturer, American Paper Optics, still prints the 3-year expiration warning out of an abundance of caution.

If you don't plan to reuse your eclipse glasses, you could:

• Donate them to Astronomers Without Borders. The group collected tens of thousands of glasses for distribution in South America, Asia and Africa after the 2017 Great American Total Solar Eclipse. 
• Recycle them. Remove the lenses, and recycle the cardboard.