Are there any tools around that can clean empty space on disks?
I'm not too worried about doing this for secure deletion purposes, I just want to get a good result from a compressed image of the disk.
NB: I tend to use: dd if=/dev/hdb | gzip > hdb.dd.gz .. but there's probably a much better way to do this. Usually it's an NTFS disk but in this particular case it is ext3.