How do I clean up my account after testing without signing up again?

You do not need to sign up again. You can clear things yourself.

1. In Contacts, select the contacts you do not want and delete them.
2. To remove a view, right click it and choose Delete view. Then add a new view, for example a table view or a board view, to get a fresh default view.
3. For custom fields, go to Settings, then Custom fields, then My custom fields, and delete the ones you do not want.
4. Delete any test websites and agents you no longer need.