Basically the following procedures are best practices:
a. Hard Drives – Triple over-write or degauss
b. Tapes – Degauss
c. Compact Disks – Incinerate or
d. Paper - Shred
e. Floppy diskettes – degauss, overwrite, or the
removed internal plastic mylar surface can
Bottom line: Anything containing a microchip or plastic Mylar recording surface (iron oxide layers) can contain SBU information.