XMLP_SCHED_DATA table cannot be purged

The BIP purge script did work in test environment, but in production cannot be used it because it takes tool long time - ORA-01555 Snapshot Too Old after a couple of days. Is there another way of purging the XMLP_SCHED_DATA table (which is too big and cannot be purged anymore)?

Recreating the scheduler is not suitable for the customer  (there are many scheduled reports to keep in the tables after the purge)

Customer asks if he can truncate a table from BI Publisher (BIPLATFORM schema) - XMLP_SCHED_DATA table:

1. Is it any live data in XMLP_SCHED_DATA which the scheduler are depending on?