Nothing will beat the speed of this shredder rosie...
I suspect Rosie would have a hard time of it. You'd need a much more serious shredder. I've used a bandsaw (kind of fun), but usually I just drill a hole in them. ;-)
Oh, back in service... Unless you got something you are real paranoid about, simply either:
1) Usually putting on a new filesystem and filling it up:
1a) Linux: mkfs -t ext2 /dev/hda ; mkdir /tmp/1 ; mount /dev/hda /tmp/1 ; mkfile 100g /tmp/1/myfile
or
1b) mkfs -t ext2 /dev/hda ; mkdir /tmp/1 ; mount /dev/hda /tmp/1 ; dd if=/dev/zero of=/tmp/1/myfile bs=1024 count=1000000)
2) zeroing the drive prior to reformatting (dd if=/dev/random of=/dev/hda ; mkfs -t ext3 /dev/hda).
Should be fine. The ability to read data back from overwritten data is pretty special and I wouldn't sweat it too much.
Old data can be restored from a hard drive that has been fdisked and formatted. Even if a new OS is installed over top.
Look for something that can do 7 passes and mix up what it is writing on each pass. Not just all 0's or 1's.
Reference for something that does this?
-john