When does Jenkins clean up old builds? I have existing Jenkins (2.90) jobs that are taking up disk space. When I enable the "Discard Old Builds" option I don't see any cleanup going on in the folder on the builds older than 7 days.

When does Jenkins do this cleanup? Or does it only apply for new builds after I apply the setting?
Per the Jenkins documentation:


  Cleanup per project/job is performed after that job runs.
  
  As of v2.221, cleanup will also periodically run using the new Global Build Discarders (even if a job has not recently been run).


Source.