NotchMindDelete one item
Open clipboard history, select the item and press ⌘ ⌫.
Keep fewer items
Lower Keep eligible clipboard items in Settings → Smart Mode. Older items beyond the new number are removed.
Clear everything recent
Turn off Keep clipboard history in Settings → Smart Mode. NotchMind stops recording and deletes the recent items. Turn it back on to start a fresh history.
Pinned items and items you saved are kept. Unpin them with ⌘ P, or delete them with ⌘ ⌫.
Delete everything, including pinned items
Open Settings → General → Support and choose Clear Clipboard History. After you confirm, it deletes saved clipboard items, the fingerprints of secrets Secret Guard saw, and any secret types you told it to ignore, so Secret Guard warns about every type again.
Remove it from the Mac completely
The history lives in ~/Library/Application Support/NotchMind. Quitting NotchMind and deleting that folder removes it, along with the Tray and reminders. See uninstall NotchMind.