cd /Volumes/"The name of the drive, in quotes"
sudo rm .hidden
sudo rm -r .vol
sudo rm -r Network
sudo rm -r System
sudo rm -r Volumes
sudo rm -r automount
sudo rm -r bin
sudo rm -r cores
sudo rm -r dev
sudo rm etc
sudo rm mach
sudo rm mach.sym
sudo rm mach_kernel
sudo rm -r private
sudo rm -r sbin
sudo rm tmp
sudo rm -r usr
sudo rm var
Now, wouldn't it be nice if all those folders were in /System so you could delete it all in one fell swoop? Oh well...