best way to delete old RMAN backups

Hi, I have setup the RMAN retention policy to recovery window of 35 days and controlfile file keep time is 35 days. I am using the RMAN in not catalog mode and backing up to the SBT_TAPE. I need to delete  backups older than 35 days and I am using the below scripts. Please suggest me. Is it correct method or not?

run {
allocate channel ch1 type 'sbt_tape'
parms='BLKSIZE=1048576,SBT_LIBRARY=$ORACLE_HOME/lib/libddobk.so,ENV=(STORAGE_UNIT=unit_name,BACKUP_HOST=host_name)';

delete noprompt obsolete;
crosscheck backup;

RELEASE CHANNEL ch2;
}

Thanks