diff --git a/Ubuntu-16.04-Root-on-ZFS.md b/Ubuntu-16.04-Root-on-ZFS.md
index 197db71..3a9f627 100644
--- a/Ubuntu-16.04-Root-on-ZFS.md
+++ b/Ubuntu-16.04-Root-on-ZFS.md
@@ -56,10 +56,14 @@ If you have a second system, using SSH to access the target system can be conven
 
 ## Step 2: Disk Formatting
 
-2.1  If you are re-using any disks which were previously in an MD array, zero the MD superblock now to avoid corruption if MD were to try to assemble the old array.
+2.1  If you are re-using a disk, clear it as necessary:
 
+    If the disk was previously used in an MD array, zero the superblock:
     # mdadm --zero-superblock --force /dev/disk/by-id/scsi-SATA_disk1
 
+    Clear the partition table:
+    # sgdisk --zap /dev/disk/by-id/scsi-SATA_disk1
+
 2.2  Partition your disk:
 
     Run this if you need legacy (BIOS) booting:
diff --git a/Ubuntu-16.10-Root-on-ZFS.md b/Ubuntu-16.10-Root-on-ZFS.md
index dcfeb55..9358887 100644
--- a/Ubuntu-16.10-Root-on-ZFS.md
+++ b/Ubuntu-16.10-Root-on-ZFS.md
@@ -54,10 +54,14 @@ If you have a second system, using SSH to access the target system can be conven
 
 ## Step 2: Disk Formatting
 
-2.1  If you are re-using any disks which were previously in an MD array, zero the MD superblock now to avoid corruption if MD were to try to assemble the old array.
+2.1  If you are re-using a disk, clear it as necessary:
 
+    If the disk was previously used in an MD array, zero the superblock:
     # mdadm --zero-superblock --force /dev/disk/by-id/scsi-SATA_disk1
 
+    Clear the partition table:
+    # sgdisk --zap /dev/disk/by-id/scsi-SATA_disk1
+
 2.2  Partition your disk:
 
     Run this if you need legacy (BIOS) booting: