[root@krypton spool]# postqueue -p|grep yahoo
6EC102381AC      816 Mon Mar 19 08:44:38  kwxlbd@yahoo.com
69065238189      816 Mon Mar 19 11:04:23  kqqzpj@yahoo.com
6BB2B2381C4      816 Mon Mar 19 14:27:24  kazkeh@yahoo.com
1E6AA2381AE      816 Mon Mar 19 11:04:37  kqqzpj@yahoo.com
0C1422381AB      816 Mon Mar 19 06:22:12  kyymhn@yahoo.com
CC8AA2381A9      816 Sun Mar 18 20:18:25  kjnyfp@yahoo.com
291E62381A8      816 Sun Mar 18 17:56:58  kpmitg@yahoo.com
9222C238198      816 Sun Mar 18 11:54:34  kfzppk@yahoo.com
D68C62381AA      816 Mon Mar 19 03:57:43  kpjzma@yahoo.com

[root@krypton spool]# delete_from_mailq k.*@yahoo.com
postsuper: 69065238189: removed
postsuper: CC8AA2381A9: removed
postsuper: 291E62381A8: removed
postsuper: 6EC102381AC: removed
postsuper: 6BB2B2381C4: removed
postsuper: D68C62381AA: removed
postsuper: 1E6AA2381AE: removed
postsuper: 0C1422381AB: removed
postsuper: 9222C238198: removed
postsuper: Deleted: 9 messages