RMAN - Deleting old backupsets

Hi,

My company is using oracle's RMAN for backups. We have 2 databases one for the production and one for the RMAN's catalog.

Our backup scheme is to do a full backup (level 0) every week and an incremental backup (level 2) every day. All backup sets are written to disk.

1. Is it safe to delete old backup sets - ones from before the last full backup ??
2. I thought of just deleting the old backups files using OS commands. Is there anything that should be removed from the catalog ?? What's the best / safest way to delete old backups both from the file-system and the RMAN's catalog ??

Any help will be appriciated!

10x

                                  Shaul