I have heard from a couple of people who are real concerned about security, that they wanted sandbox to not only delete the content but to "shred" it on exit.
Overwrite the specified FILE(s) repeatedly, in order to make it harder
for even very expensive hardware probing to recover the data.
cat untrustedcontent | sandbox --shred sandbox -M filter.sh > /tmp/trustedcontent
sandbox -X -s -W metacity firefox
Dan Walsh's Blog
- sandbox can now shred in Fedora 18 and RHEL7