Cleans the content (files and folders) within the directory that have passed their expiration date. Every server directory has the max file age and cleanup mode parameter that govern when a file created inside is supposed to be cleaned up. The server directory cleaner automatically cleans up the content within server directories at regular intervals. However, you can explicitly clean the directory by invoking this operation.
The response format. The default response format is html.
Values: html | json | pjson
Below is a sample POST request for clean:
POST /webadaptor/admin/system/directories/arcgisoutput/clean HTTP/1.1 Host: machine.domain.com Content-Type: application/x-www-form-urlencoded Content-Length:  f=json
JSON Response example