So, here's the steps for removing all traces of an iSCSI volume.
Step 1: Find the iSCSI Session
[root@localhost]# iscsiadm -m sessiontcp: [1] 192.168.0.100:3260,1 iqn.2001-05.com.emc:0-af1ff6-c57ac0bd5-712a2878fd0
533c6-backuppc (non-flash)
Step 2: Disable (logout) current iSCSI session
[root@localhost]# iscsiadm --m node -T iqn.2001-05.com.emc:0-af1ff6-c57ac0bd5-712a2878fd0533c6-backuppc --portal 192.168.0.100:3260 -u
Logging out of session [sid: 1, target: iqn.2001-05.com.emc:0-af1ff6-c57ac0bd5-7
12a2878fd0533c6-backuppc, portal: 192.168.0.100,3260]
Logout of [sid: 1, target: iqn.2001-05.com.emc:0-af1ff6-c57ac0bd5-712a2878fd0533
c6-backuppc, portal: 192.168.0.100,3260] successful.
Step 3: Double check that session is logged out
[root@localhost]# iscsiadm -m session iscsiadm: No active sessions.
Step 4: Permanently delete iSCSI session
[root@localhost]# iscsiadm -m node -o delete -T iqn.2001-05.com.emc:0-af1ff6-c57ac0bd5-712a2878fd0533c6-backuppc --portal 192.168.0.100:3260
Step 5: Stop iSCSI from running (since targets are gone)
[root@localhost]# service iscsi stopStopping iscsi: [ OK ]
[root@localhost]# chkconfig iscsi off