How to clean up trashbin of owncloud without trashbin:cleanup command?

How to clean up trashbin of owncloud (owncloud help trashbin), when

# sudo -u www-data ./occ trashbin:cleanup                                         
  There are no commands defined in the "trashbin" namespace.

/var/www/owncloud# sudo -u www-data ./occ config:list | grep -A 6 trashbin 
        "files_trashbin": {
            "enabled": "no",
            "installed_version": "0.9.1",
            "types": "filesystem"
        },

but

/var/www/owncloud/data/myuser/files_trashbin# du -hcd 1
307M    ./files
4,0K    ./versions
4,0K    ./keys
307M    .
307M    total

…and in the other user namespaces are also some data in files_trashbin.

The web UI does not give me any hint to any trashbin (well, understandable regarding above command).

Background: I prepare for a nextcloud migration the server to not exceed maximum disk usage.