1. Take hard drive out of computer.

2. Find a fencepost in an appropriately isolated location on your farm or a buddy's remote property.

3. Stand hard drive on edge on fencepost.

4. Take your 12ga shotgun, load one high-brass shell with 1 ¹/₈ oz. of #6 shot. Steel shot is preferred, but copper or nickel-plated lead will work OK. You'll typically see these loads as "field loads."

5. Pace off about five paces from the fencepost with the hard drive on top.

6. Aim carefully at the round area on the hard drive which shows where the platters are.

7. Pull trigger.

8. Pick up mess.

I have used this technique on several hard drives with complete success. Not even a scanning electronic microscope can read the data after this disposal process.

Edit: Almost forgot: I use a modified choke.