Octo.exe can be used to cleans all offline workers from a worker pool.
Learn about worker pools.
Usage: octo clean-workerpool [<options>] Where [<options>] is any of: WorkerPool Cleanup: --workerpool=VALUE Name of a worker pool to clean up. --health-status=VALUE Health status of Workers to clean up (Healthy, Unavailable, Unknown, HasWarnings, Unhealthy). Can be specified many times. --disabled=VALUE [Optional] Disabled status filter of Worker to clean up. --calamari-outdated=VALUE [Optional] State of Calamari to clean up. By default ignores Calamari state. --tentacle-outdated=VALUE [Optional] State of Tentacle version to clean u- p. By default ignores Tentacle state Common options: --help [Optional] Print help for a command --helpOutputFormat=VALUE [Optional] Output format for help, only valid option is json --outputFormat=VALUE [Optional] Output format, only valid option is json --server=VALUE [Optional] The base URL for your Octopus Server, e.g., 'https://octopus.example.com/'. This URL can also be set in the OCTOPUS_CLI_SERVER environment variable. --apiKey=VALUE [Optional] Your API key. Get this from the user profile page. Your must provide an apiKey or username and password. If the guest account is enabled, a key of API-GUEST can be used. This key can also be set in the OCTOPUS_CLI_API_KEY environment variable. --user=VALUE [Optional] Username to use when authenticating with the server. Your must provide an apiKey or username and password. This Username can also be set in the OCTOPUS_CLI_USERNAME environment variable. --pass=VALUE [Optional] Password to use when authenticating with the server. This Password can also be set in the OCTOPUS_CLI_PASSWORD environment variable. --configFile=VALUE [Optional] Text file of default values, with one 'key = value' per line. --debug [Optional] Enable debug logging --ignoreSslErrors [Optional] Set this flag if your Octopus Server uses HTTPS but the certificate is not trusted on this machine. Any certificate errors will be ignored. WARNING: this option may create a security vulnerability. --enableServiceMessages [Optional] Enable TeamCity or Team Foundation Build service messages when logging. --timeout=VALUE [Optional] Timeout in seconds for network operations. Default is 600. --proxy=VALUE [Optional] The URL of the proxy to use, e.g., 'https://proxy.example.com'. --proxyUser=VALUE [Optional] The username for the proxy. --proxyPass=VALUE [Optional] The password for the proxy. If both the username and password are omitted and proxyAddress is specified, the default credentials are used. --space=VALUE [Optional] The name or ID of a space within which this command will be executed. The default space will be used if it is omitted. --logLevel=VALUE [Optional] The log level. Valid options are verbose, debug, information, warning, error and fatal. Defaults to 'debug'.