Depending on your browser, there are different ways to clear your passwords.
The most common is Internet Explorer. To do so, click on Tools, then goto Internet Options.
Depending on your version, the option screen may look different. Click on Delete under the Browing History subsection and that will delete any saved passwords used. You can not be specific which password to delete, this will do it all.
If you use another browser, let me know and I can address this for you.
Hope this helps!

