I am supposedly an administrator of our church Trello system. We have many "collaborators" who are no longer in the area. There are also three "Private Boards" that no one associated with the church knows anything about, such as who "owns" the board and who, if anybody are collaborators on these boards. There are supposedly 4 guests on these boards.
Also, I have tried to remove two guests whose accounts I can see; they "disappear" but then are restored within minutes.
What are the procedures for removing Private Boards and removing Guest accounts?