Old equipment must be responsibly and carefully disposed of. The best solution is to pass on to others who can use the equipment, if it still is in good working order. Otherwise, there are many stores that will take in older equipment for free or a small charge.

http://www.pcmag.com/article2/0,2817,2383568,00.asp

We love our computers and smartphones and gadgets. That is, until they stop working. Then these devices and their peripherals such as printers and monitors, not to mention the cases and batteries and cables and accessories, often become burdensome electronic garbage.

Gadgets aren’t made to last, after all. No computer or phone maker is going to mind if you upgrade every year or two. In fact, they count on it. Consequently, all this junk ends up in the back of your closet or stored in your garage, collecting dust, because you aren’t sure what to do with it.

The best thing to do is donate or recycle it. Contribute your old computers and phones to groups that will fix and clean them and put them back into circulation. Even the oldest computer—something you consider the most obsolete of digital dinosaurs—can probably be used by someone.

There are times, though, when a device is too far gone. There’s nothing that can be done to bring it back to life again. Even a charity doesn’t want unusable rubbish. That junk—called e-waste—is potentially dangerous. Electronics are filled with “heavy metals” (read: toxic metals) and carcinogenic chemicals that are fine when you’re using them, but not so much when sitting in a landfill or, worse, when people recycle them incorrectly. Thousands of tons of e-waste are shipped overseas yearly to countries like China and India, where it gets dumped and maybe burned, which puts mercury and lead into the air.