Excellent timing, I've just announced on a mailing-list my first public AMI. So I'll have to check tomorrow if I made mistakes on the way :) (I'm pretty sure I haven't left anything confidential, but there might be some cruft with my keys…)
<advert><p>libguestfs[1] that I helped to write provides some solutions for this, including access to secure scrub utilities[2] and this script[3] for removing "empty" space in a disk image.<p></advert><p>[1] <a href="http://libguestfs.org/" rel="nofollow">http://libguestfs.org/</a><p>[2] <a href="http://libguestfs.org/guestfish.1.html#scrub_file" rel="nofollow">http://libguestfs.org/guestfish.1.html#scrub_file</a><p>[3] <a href="https://rwmj.wordpress.com/2010/10/19/tip-making-a-disk-image-sparse/" rel="nofollow">https://rwmj.wordpress.com/2010/10/19/tip-making-a-disk-imag...</a>