If you got a pair of ISO-certified solar eclipse glasses to watch as the moon passed between the sun and the Earth, don’t throw them out. The materials can be recycled and reused thanks to national groups who collect thousands of glasses for redistribution.

Astronomers Without Borders started collecting eclipse glasses in 2008. U.S. National Coordinator Keith Sowell said the glasses do not expire.

Marylanders can drop off their used eclipse glasses at any one of seven Warby Parker retail stores in the state that will be used as hubs for Astronomers Without Borders to gather the used glasses.

“We recondition them and we send it back out to people in third-world countries and rural areas to people who might be unable to obtain them,” Sowell said. “They’re good for years after you sanitize them and clean them up.”

If the glasses have the right kind of filters and the lenses remain attached to the frames, they will last.

Eclipse Glasses USA also collects donations of used and undamaged eyewear through the mail.

And for each five-pack of glasses purchased through Eclipse Glasses USA, the manufacturer will donate one pair of glasses to a school in Latin America, where an annular eclipse is expected in October 2024, according to the company’s website. That program has brought in 30,000 pairs of glasses as of April of this year, the website said.

According to Sowell, eclipses occur each year all over the world. Eclipse glasses donations to Astronomy Without Borders and Eclipse Glasses USA are inspected for safety and sent around the world.

“In places where there are limited resources, we give the glasses to those people so that they can watch the solar eclipse without burning their eyes — it’s all about safety,” Sowell added.