CEPH: Ceph how to uninstall a Ceph cluster

So... ya f*cked it all up and want to start again - luckily, there's a command for that

# This was run on the ceph-deploy node, in the ~/ceph directory where the keys and ceph.conf were stored. 
cd ceph 
cp ceph.conf ceph.conf.bck
ceph-deploy purge ceph-osd1 ceph-osd2 ceph-osd3
ceph-deploy purgedata ceph-osd1 ceph-osd2 ceph-osd3 # this failed as device/resource busy. guess a reboot will sort but cant tests that atm. to be updated. 
ceph-deploy forgetkeys

And now go back and run ceph-deploy new...

One additional note:

• On disks that had already been installed with Ceph run:

#  on all nodes previously installed / disks
parted /dev/sda
mklabel gpt
quit
partprobe
# not sure if this is needed but previous commands would exist with 
#  /usr/sbin/sgdisk --verbose --largest-new=1 --change-name=1:ceph data --partition-guid=1:f4784a2e-9d59-47fd-949e-1ef6d434f108 --typecode=1:89c57f98-2fe5-4dc0-89c1-f3ad0ceff2be -- /dev/sdc