You can use ManageFlitter for fast and easy unfollowing on Twitter, but is a catch: although it lists all your followers in pages of 100 with checkboxes, but without  a "Select All" option.

Twitter put their foot down on "Mass Unfollowing" in April, 2010. All twitter supplemental  applications either had to remove "Bulk Unfollow" options or the "Select All" option to continue to operate within Twitter’s updated Terms of Service.

The "select all" function  is just a JavaScript call and happens in your browser, so all one has to do is find a plugin/add-on for the browser to allow the "select all" function.

An add-on is available for FireFox 3.0 called Check All but it doesn’t work in FireFox 3.6. This does have another version out that is supposed to work for Firefox 1.5-3.6 Check All 0.2.3

Another Mozilla add-on is CHECKFOX  that also enables quick check/uncheck of checkboxes, and works in Mozilla Firefox 3.6. You have to select a text area, encompassing the check boxes you want, and then right-click the text area and click on "check" in the context menu. It'll then check any boxes within that selected area. It's a little tough, because the text isn't always uniform or in the same field (for instance tables), and the checkboxes do not highlight – making it hard to tell if you have the correct boxes selected. Give either of them a try.

Steps To Bulk Unfollow On Twitter:

1. Download Check All 0.2.3 or CHECKFOX 
2. Next go to ManageFlitter and login to your Twitter account.
3. Click “Show All” and you’ll be presented with a list of your followers in pages of 100 with a checkbox next to each and an Unfollow button on the left.
4. Hit Ctrl+A for "select all",
5. Riight click on a highlighted area and you’ll see the new plugin option “Check All Selected Checkboxes”,
6. Click Unfollow,
7. Click Next, Ctrl+A, Right Click, Select All Checkboxes, Unfollow.

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