How to Drop a RAC database

$> srvctl stop database -db orcl

SQL> startup mount;
SQL> alter system set cluster_database=false scope=spfile sid='*';
SQL> shutdown immediate;
 
$> rman target /
RMAN> startup force mount;
RMAN> sql 'alter system enable restricted session';
RMAN> drop database including backups noprompt;
RMAN> exit;
 
$> srvctl remove database -db orcl -noprompt