I can now email to vopa821kiwu using a particular category (lhs), and can use that as a running blog for non-imperative information that I do not want cluttering my notebook.
Clipboard history managers exist. Mac option is Unclutter
Certain clipboard managers can blacklist passwords
Password managers can be used, e.g. One Password (just need to remember one password) or Last Pass – accessible via browser OR via browser extension and allows fingerprint login! Can sync across multiple devices. Can either just copy and paste a password yourself, OR it can automatically paste into sites.