Have Arduino Delete Tweet

I have a working Arduino sketch that posts a tweet each time my garage door goes up or down. (See: http://www.allmytweets.net/?screen_name=@whatta_nerd )

Question: What would it take to make Arduino delete the oldest tweet prior to posting a new one ? Modify (add to) Twitter Library ? I don't see any "delete" capability in it, as it is.

I don't really know where to start. This sounds like something that someone might have investigated before.

BobW