methods to send self destructing emails

Hey Lemmy!

Exactly as the title says, where self-destructing means that no matter what email provider I, or my recipients use, the email will be gone after a set amount of time.

The methods I have come up with are:

• using a PrivateBin or PasteBin link.
  • requires the recipient to click on a link that opens in another app/tab
  • easy to set up
• using an HTML remote content stylesheet with CSS ::after to inject the body text of the email; then, if I control the server, I can delete the stylesheet and the email will be gone.
  • embedded in the email, but plain text only. I'm not even sure if it can do line breaks.
• loading an SVG from a remote source

Does anyone have more methods?