Data Cleanup
To manually delete stale data from your system you can do so via the Data Cleanup menu item under Data Management.
Click the calendar icon to choose a date and the clock icon to specify a time. Then click the Clear Old Data button to start the purge.
This is a permanent operation, deleting data in this manner is non-reversible.
SCS automatically cleans old data for you so this operation shouldn't be nessecary though it might be a good idea to run it annually just to be sure.
Depending on the amount of data there is in your system this could be a long running operation. It is advisable to kick the job off when you are on shore or SCS is not actively being used (potential performance impacts).