Twitter direct messages can be deleted individually and if you don’t regularly delete your DM’s then it makes a big number which is of no use and unnecessary. And manually deleting each of the DM by clicking the delete button beside each of them would be very time consuming.
DM Deleter or DM Whacker is a browser bookmarklet that helps you delete all the Direct messages in your inbox and sent items together at once. And this saves lot of time as manually deleting each of the DM when they are hundreds, would consume lot of time.
Its still in beta stage and can go wrong sometimes but you can still give a try when you have decided that you want to delete the big bulk of DMs.
Drag the link below to your bookmarks bar and then open your Direct Messages page in Twitter. Click the bookmarklet you created and select whether you want to delete all direct messages, or just direct messages from a specific user (No @ in front of their name).
Please note that when you delete a message from your Sent mailbox, it will delete it from the recipient’s Inbox. The same applies for messages you have received.
The bookmarklet works with Firefox 3, Google Chrome, Safari an Flock browser but has given problems with FF2.
It is also called DM Whacker and you can add the bookmarklet from Here.