Solution: Here are some commands to run to clean out the indexed data.
Note: You must first stop the Splunk service before you can run any of these commands:
This example tells Splunk to remove event data in all indexes (because no index argument is specified).
./splunk clean eventdata
This example removes indexed event data from the internal index and forces Splunk to skip the confirmation prompt.
./splunk clean eventdata internal -f
Note: It can also be helpful to flush the event logs of the Server as they might refer to the server's previous name which will just add junk to Splunk's indexes.