UnTweeps follows a simple principle. See who has not tweeted in 30, 60 or 90 days and then stop following them. A quick way to clean up and provide some contact management. The interface has a choice between utilizing Oauth, so they never store your username and password or the standard way of giving it to them. Once they pull information on who you follow, it is simple point and click.
You can then “unfollow” the ones you want by leaving the check box checked. Uncheck the ones you want to keep
While you really gain nothing by unfollowing someone that went stale, it is a good practice. However, keep in mind they may start again at any time and you will need to refollow them.
I ran mine through and only found 1 account that had not tweeted in 90 days or more. I feel pretty good. I might try it again for 60 days, but I think 30 is too short. People should be able to take some break, don’t you think?