DarkRP - How to clear admin/Superadmin list

Anyone know a way to basically return everyone to “user” on my servers through Fadmin?

I’m going to start looking for new staff, lol.

It depends, are you using MySQL or not?
Are you using ULX, FAdmin, both or something else?

(Just added everything, if he joins back / logs out.)

If you are using FAdmin, with MySQL, you need to delete the rows in the fadmin_playergroup table.
If you are using FAdmin without MySQL, you need to download the sv.db file from your server, edit it with a SQLite database browser to delete the rows from the above table.

If ULX, delete the users.txt file in the data folder.