Safari 6 makes it easier than ever to manage and remove passwords stored for the various websites you visit from the Mac. If you want to clear a single or all stored passwords, here’s all you need to do:

• Open Safari’s Preferences from the Safari menu and click on the “Passwords” tab
• Select the website you want to remove the stored password from and then either click the “Remove” button or hit the Delete key
• Alternatively, click “Remove All” or use Shift+Click to select a group of logins and passwords to remove more than a single stored password at a time

If you have many stored logins for a ton of websites, use the search field within the Passwords tab to find groups. You can also use the search function to narrow down websites by username used to access them, which is great if you use a common junk login for sites you’d rather not have a primary login associated with.
For iPhone, iPad, and iPod touches, this can also be done in iOS through clearing Safari Settings.