Disk Pools primary storage using tsm 5.5

We are currently using san disk as our primary storage pools. I know the reclaim command is used to do reclaimation on lto tapes to remove expired backups and rebuild the lto's. Can someone tell me what command can be used on the disk pools that could remove expired backups.
We are currently running tsm 5.5 on aix 6.1

thanks for any help in advance.