Have you ever wondered if you could schedule your tweets to self-destruct? I am here to tell you that you can with a tool called Spirit.
All you have to do is visit http://twitterspirit.com/ and enable the service. Then, the next time you include a hashtag like #18m (for minutes), #7h (for hours) or #13d (for days) in your message, the latter will be gone after the allotted time has run out.
Note that the minimum time for deletion is one minute and that the placement of your hashtag in the Tweet does not matter.