I would like to clear the call logs from the UCCX.
You can use the RTMT (Real Time Monitoring Tool) to delete the log file from the server.
Login to RTMT. Go to Trace and Log central -- Collect Files.
Select the specified logs which you need to delete. When you proceed next, choose the timestamp for which you need to delete.
On the same window, you will see an option "Delete Collected Logs from the Server". This is unchecked by default. You will need to check this and proceed.
This will remove the specified logs, for the particular time frame from the server.
Hope this helps!