CentOS - Mar 2017 - have udev to ignore/hide a scsi disk - but how?

hi everyone

I've been playing and trying to tell udev to ignore and not 
create symlinks in /dev but I fail.
Hoping this is the one: ENV{ID_SERIAL}== I've tried:
ENV{SYSTEMD_READY}:="0"
OPTIONS+="last_rule"
even
ENV{UDISKS_IGNORE}="1"

but udev tests would still show:  ACTION=add and symlinks 
created.

Would share an advice?
many thanks,
L.