[Wistar]

… and bury it at least 8 feet deep on land no closer than a mile from your residence.

[wpasc]

seems to be careless not to burn current residence to the ground as well

[quickthrower2]

Then salt the earth

[guerrilla]

I think 6 feet should be enough in most cases, if you're short on time or energy.

[bitwize]

Turn off your computer and make sure it powers down,

Drop it in a 35-foot hole in the ground,

Cover it completely, rocks and boulders should be fine...

[FeistySkink]

Pretty sure you could still recover the flash-based memory. Unless you're dropping into acid or lava.