When you first hear about it, you think "What's the big deal?", but then you quickly find that you use it pretty often.
- If the text to sanitize is a single line: Win+R, paste, select all, cut, Esc (to close "Run" window)
- If it's multiple lines: Win+R, notepad, Enter, paste, select all, cut, Alt+F4 (to close notepad)
On Linux, I usually switch to Emacs, switch to a scratch buffer, then do the paste-and-cut-again dance in it.
You can set "dom.event.clipboardevents.enabled" in Firefox to disable all of that, but some websites can break horribly because they just assume it's there and will do $weird_shit if it's not. e.g. Twitter and Facebook messenger for example; it's not that you get an error either, it just behaved in really odd ways. It seems Twitter works now in quick test, and I no longer need to use Facebook Messenger, so let's try setting it again.
There's also "clipboard.plainTextOnly", but it doesn't seem to work, or maybe it does something different from what I expect.