How best to recycle an OLD Apple iBook with the hard drive still in place?

An old Mac can work as a recipe-storage library, for instance, and that antique iBook can be a backup drive. But when you’ve run out of ways to reuse or repurpose your old Mac, what’s the best way to recycle it? Here are a variety of solutions—from low-effort to time-intensive—that’ll keep your conscience and your closet clear.

California, Maine, Maryland, Minnesota, Oregon, Texas, and Washington now have laws regulating where and how you can dispose of unwanted electronics. But in most others, it’s still legal to throw your computers in the trash. According to a recent 60 Minutes report, an estimated 130,000 computers end up in the garbage annually.

There are all kinds of good reasons not to make yours one of them: lead, mercury, and hexavalent chromium are three of the best. These substances, which are embedded in our computers’ assorted parts, are just a few of the toxins that can be released into the environment if an old computer or iPod is just tossed onto a scrap heap and burned. Once in the groundwater or air supply, heavy metals and PCBs released by improperly disposed-of computers linger as cancer-causing compounds.

Before you dispose of an old computer, make sure you wipe it clean of all your data. The first step is to back up all the data on the device’s hard drives. Either copy it to your new machine or pick up an external hard drive and use that as a repository for all the old files.

To duplicate the contents of the old drive, use Time Machine. Or if your old system doesn’t have OS X 10.5, try Carbon Copy Cloner (payment requested; ). Now erase your footsteps.

Start by deauthorizing iTunes. You don’t want to later realize that you have one less machine you can play your old, pre-iTunes Plus music on. Then deauthorize any third-party programs you’ll want to reinstall on your new system.

Next, wipe your hard drive. Track down the installation discs that came with your computer (or use the ones that came with any OS X upgrade you purchased). Insert Disc 1 (CD) or the installer disc (DVD), launch Installer, and reboot the machine using the software on the disc.

Go to the Installer menu, choose Open Disk Utility, select the hard-drive icon in the column on the left, click on the Erase tab, and then click on Options. The 8 Way Random Write Format will scramble your data nicely. Now that your soon-to-be-departed Mac is wiped clean, it’s ready for recycling or donation.

If your computer is still in working order, consider donating it. The research firm Dataquest estimates that less than 5 percent of all personal computers find a second life at a charity or school. You can increase that percentage by recycling your old electronics with a nonprofit facility.

Such an organization will try to match your old electronics equipment with a school or a charity that can use it. To find a nearby nonprofit or school-based recycler, go to TechSoup’s TechFinder online directory, type in your zip code, and then narrow the results by selecting Computers or Printers And Peripherals from the Technology pull-down menu on the results page. The Electronic Industries Alliance also maintains a list of donation programs.

If your old goods are only a year or three old, you might be able to sell them for petty cash. In addition to the obvious outlets like eBay (check out its guide to selling electronics) and Craigslist, a crop of services that buy used electronics has grown online. The auction site eBay has a great guide to selling used electronics.