Before selling that old Mac, clean it out

Get rid of your Mac! Wipe it, reinstall it and ship it out! Go, go, do it now!

You'll forgive me for being a day late and a joke short for April Fools' Day, but I'm not talking about the Mac you love, but that one you've decommissioned or use desultorily that needs a new home.

I own more than a dozen desktops, laptops and servers, and recently started work on sending two of the Macs out into the wider world. They're 5 and 6 years old but operate fine, have tons of memory and can run Mac OS X 10.3 Panther.

If you love something, set it free. Rather, set its price and sell it. (And then buy a Mac mini.) But selling a used Mac as-is can be problematic. You want to avoid any stray data ending up in someone else's hands, and also put the machines in pristine condition for the next buyer. Follow these steps and you won't find yourself shipping off your precious data along with your formerly precious computer.

• Deauthorize iTunes . It is vitally important that if you've listened to any music purchased from the iTunes Music Store on the computer that you deauthorize that computer. Apple allows only five computers to share the same authorization, so don't inadvertently send one out the door. (You should also deauthorize your Mac before you send it in for service, too.) In iTunes, go to the Advanced menu and choose Deauthorize Computer.

• Copy the hard-drive contents. You may think there's nothing you need on that computer you're getting rid of, but you're wrong. You'll have erased the hard drive — and then remember that your 2003 tax document you need to import to file a 2004 return was on that computer.

Hard drives are cheap: La Cie (www.lacie.com) sells two models of 160 GB drives for $149 (FireWire 400) and $179 (USB 2 and FireWire 400 and 800).

Back up using Dantz Retrospect Desktop 6.0 (about $90, www.dantz.com). It can fully copy all Mac OS X files. If you want to clone or exactly duplicate the computer's drive, try Carbon Copy Cloner ($5 donation requested, www.bombich.com/software/ccc.html).

• Boot from a Mac OS X installation disc and wipe the drive. Make sure you have a full set of installation discs that either came with the computer or that you purchased, such as a Panther upgrade. Insert Disc 1 into the computer (if CDs) or the single installer disc (if a DVD), launch Installer, and follow its prompts: the computer will reboot using software on the CD or DVD.

If you want to fully eliminate any potential of data left on the drive from being read, simply erasing the disk isn't enough. From the Installer menu, choose Open Disk Utility. Select the hard-drive icon in the left column. Click the Erase tab. Click Options. Choose either Zero All Data (most users) or 8 Way Random Write Format (doctors, lawyers, and code crackers).

Now walk through the installation process and choose your hard drive at the stage where it presents you with one or more local drives. Click Install, and then click the Options button. Choose Erase and Install, click OK, and click Continue.

When the installation is done, the machine reboots.

• What if Panther doesn't install? Assuming you're trying to reinstall Panther on the machine, you might need to find a more recent version. I recently wiped a Power Mac that had a processor-upgrade card installed and was unable to install Panther using 10.3.0 discs.

My brother-in-law, to whom I sold the machine, had a set of 10.3.2 discs that worked fine. If you don't know anyone with another set of discs, you can take the computer to your friendly neighborhood Apple dealer and see if it can help you.

• Installed software. If you plan to include software that didn't come with the computer, make sure you hand over the original discs or installers and serial numbers of the software to the new owner. Keeping a copy for yourself is piracy, and you could wind up getting caught these days. Auction listings that describe "evaluation software" aren't fooling anyone.

Some auction sites require also that the operating system that's installed on the computer comes with discs: either the discs that shipped with the computer or a full, legitimate installer that you purchased or obtained separately. If you installed Panther, in other words, you have to have Panther discs that the seller will receive.

Do run Software Update to get the system's free Apple upgrades, however.

Unless you're keeping a Mac museum in your house, enjoy a little less clutter by selling old Macs that you're no longer using — until your current pride and joy is last century's model and it's time to move up to the latest and greatest.

Glenn Fleishman writes the Practical Mac column for Personal Technology and about technology in general for The Seattle Times and other publications. Send questions to gfleishman@seattletimes.com. More columns at www.seattletimes.com/columnists