If you have been running test schedules, the historical scheduling information on file for the test schedules will automatically be cleared as long as the test schedules were for the same time period as the real schedule. (You will see a notice appear when you click the "Commence Scheduling" button when running the real schedule that the historical information on file from the test schedules is going to be cleared.) If you want to clear all the history for all schedules, not just the ones that overlap the real schedule:
1. From an open schedule, go to the Schedule tab.
2. Click on Scheduler Settings.
3. Select Historical Data on the left.
4. Click on "Clear all historical scheduling data."
5. Click ok.
6. Close the Scheduler Settings.