steps to safely dispose of a mac desktop

Do you own another Mac, and do both have a FW port? You should be able to boot the old Mac into FW target mode, it will then function as if It were an external FW drive on the new Mac. the new Mac will be able to run Disc Utility and run the zero data format on the drive in the old Mac.

http://www.engadget.com/2009/04/27/tuaw-tip-clean-your-hard-drive-with-target-di sk-mode/

If you have a compatible retail Mac OS 8, 9, or X install disk, or a second bootable drive, you can use that instead. If not, it may be best to remove the drive from the computer; this depends on whether the computer will be sold/given away for reuse or completely disposed of.

The Disk Utility will not erase the active startup volume.

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Click here and follow the instructions. When you reach step 5, insert its original disk, restart with the C or Option key held down, use the Disk Utility to securely erase the internal drive; alternatively, you can just remove the drive from the computer.

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