US Department of Defense 5220.22-M Clearing and Sanitization Matrix
a. Degauss with a Type I degausser
b. Degauss with a Type II degausser.
c. Overwrite all addressable locations with a single character.
d. Overwrite all addressable locations with a character, its complement, then a random character and verify. THIS METHOD IS NOT APPROVED FOR SANITIZING MEDIA THAT CONTAINS TOP SECRET INFORMATION.
e. Overwrite all addressable locations with a character, its complement, then a random character.
f. Each overwrite must reside in memory for a period longer than the classified data resided.
g. Remove all power to include battery power.
h. Overwrite all locations with a random pattern, all locations with binary zeros, all locations with binary ones.
i. Perform a full chip erase as per manufacturer's data sheets.
j. Perform i above, then c above, a total of three times.
k. Perform an ultraviolet erase according to manufacturer's recommendation.
l. Perform k above, but increase time by a factor of three.
m. Destroy - Disintegrate, incinerate, pulverize, shred, or melt.
n. Destruction required only if classified information is contained.
o. Run five pages of unclassified text (font test acceptable).
p. Ribbons must be destroyed. Platens must be cleaned.
q. Inspect and/or test screen surface for evidence of burned-in information. If present, the cathode ray tube must be destroyed.
Now get back on topic!!!