How to delete old clients?

I apologize in advance if this is a duplicate topic. I had urbackup running on a machine for a long while. I’ve since reformatted that machine, and put it to other use. I don’t need the backups from that machine any more (I’m using that machine as a server now.)
I want to free up space on my backup drive by deleting those backups from that client. I don’t have that client on the UI anymore, since I reformatted it.
I just want to be able to free up the space on my drive by deleting all that data, but I don’t want to mess it up for the other machine that I have using urbackup too.
Does this make sense?

in the status page select client , remove client
it will be effective at the daily maintenance

Sorry, but that’s not my issue. The client isn’t showing on the webui because it has been reformatted. I just have the existing backups for that client on my server. I want to know the best way to delete those files.
Can I just delete them? I don’t want to mess up the other backups/clients I have.

You could try running the remove_unknown script / batch-file in the server program directory… see if they disappear, if they do it’s a win.