ClipTTL is a tiny portable program - under 100KB - which automatically clears the clipboard after 20 seconds.
This helps maintain your privacy by ensuring no-one else can come along later and view clipboard data.
It also means you're less likely to accidentally paste the clipboard contents into some other document.
Launch the program and it goes to work immediately, adding a single icon to your system tray. That's all, there's no other interface, menu, dialog box or anything else-- just left or right-click the icon to close the program down.
If the 20 second timeout is too short for you, pass it your preferred value (in seconds) on the command line, like clipttl.exe 60