How to safely remove a corrupted cluster?

If the saying "to learn you have to make mistakes", I'm "learning"...:

I removed a cluster's folder without using pg_dropcluster... sio now I have
a corrupted cluster. How can I safely remove it?

(base) marco(at)pc:~$ pg_lsclusters
Ver Cluster Port Status Owner Data directory Log file
11 fabmnet 5433 down <unknown> /var/lib/postgresql/11/fabmnet
/var/log/postgresql/postgresql-11-fabmnet.log
11 main 5432 online postgres /var/lib/postgresql/11/main
/var/log/postgresql/postgresql-11-main.log

(base) marco(at)pc:~$ pg_dropcluster 11 fabmnet
Warning: corrupted cluster: data directory does not exist
Warning: systemd was not informed about the removed cluster yet. Operations
like "service postgresql start" might fail. To fix, run:
sudo systemctl daemon-reload
(base) marco(at)pc:~$ sudo systemctl daemon-reload
[sudo] password for marco:
(base) marco(at)pc:~$ pg_dropcluster 11 fabmnet
Warning: corrupted cluster: data directory does not exist
Warning: systemd was not informed about the removed cluster yet. Operations
like "service postgresql start" might fail. To fix, run:
sudo systemctl daemon-reload

Marco