Instructions
 
Log in to your account on the "Soldier Front" website. You can do this by navigating to the site and clicking "Sign In" at the top-right of the page. Once you log in, you will be returned to the game's main page and, if you are the leader of a clan, you will see a "Clan Management" tab. 
Click "Clan Management" from the top-right of the page. A number of options relating to the clan will be displayed. 
Click "Disband Clan" near the bottom of the list. A confirmation screen will appear. 
Click "Yes" to instantly disband the clan and remove all of its members.