You could install Chrome OS on them, at least then they can safely be used on the internet. There may be charities in your city that accept donations of computers like that for people who cannot afford one.
https://www.xda-developers.com/how-to-install-chromeos-flex-on-an-old-laptop/
You could also install Linux and use them for different projects (though something like a Raspberry Pi is probably going to have more speed and use less electricity.)