Killing zombies in terminal

Cleaning my iPods. One had all OS untill 8.5 - why would I need them on the iPod? (I wouldn't, if I had any space on my portable hard drive, sigh). Another iPod got just rid of 1.5 GB of Newton software. Shuffle will get rid of everything that is reconverted. And maybe get some space as a USB stick (even though I notice I do 'need' to have memory sticks of the size of a few DVDs).

Among the interesting items I had on the iPods... old chat transcripts. Old photos of my 1/2, and some unix sfuff.
Of those, something useful might be killing the zombie processes.
ps aux | grep Z