Got a bunch of eclipse glasses on your hands? Don't throw them away yet!
Eclipse glasses can be used indefinitely, according to NASA, to view the uneclipsed sky... so long as they are in good condition. That means no scratches, bends, holes, or fingerprints. If your glasses get dirty, don't try to wash the lenses; that will most likely ruin them. You can wrap them in tissue paper, store them some place where they won't get damaged, and reuse to your hearts content!
If you got all the use out of them that you want, hang onto them just a little while longer. Astronomers Without Borders is creating a program that you will be able to send your used glasses to, so that students in Asia and South America can view the eclipse when it passes their way in 2019.