Delete backups from old incarnation in rman

I did a refresh on a non-production database and these are the incarnations:

List of Database Incarnations

DB Key  Inc Key DB Name  DB ID            STATUS  Reset SCN  Reset Time


1       1       ORCL     1355555557       PARENT  1          20-DEC-11

2       2       ORCL     1355555557       CURRENT 12         17-JUL-14

How do I delete the backups from the old incarnation since they’re not needed anymore?
Any help would be greatly appreciated.
Thanks.