Securely erasing flash memory is surprisingly hard. >Whole-disk wiping techniques faired only slightly better with SSD media. In the most extreme case, one unn

Securely erasing flash memory is surprisingly hard. >Whole-disk wiping techniques faired only slightly better with SSD media. In the most extreme case, one unnamed SSD model still stored 1 percent of its 1 GB of data even after 20 sequential overwrite passes on the entire device. http://www.theregister.co.uk/2011/02/21/flash_drive_erasing_peril/ http://www.theregister.co.uk/2011/02/21/flash_drive_erasing_... I wonder how hard it is on SD drives. Meanwhile this forum claims the NSA mandates physical destruction https://discussions.apple.com/docs/DOC-5521 https://discussions.apple.com/docs/DOC-5521