Sometimes you may need to clear the cookies saved by your favorite browser, usually the cookies are harmless but at times your PC may be infected through a saved cookie. Also if you are editing your website but do not see the changes being reflected you may need to clear your browser's cache & cookies.
Here are some basic instructions on how to clear the cookies of your browser:
Internet Explorer:
Tools -> Internet Options -> General -> Delete Cookies (under the Temporary Internet Files section)
Firefox:
Tools -> Clear Recent History -> Select time frame from the dropdown menu(if you wish all cookies removed - select Everything) -> Mark Cookies only -> Clear Now
Opera:
Tools -> Delete Private Data -> Details -> Mark Cookies only -> Delete
Konqueror:
Settings -> Configure Konqueror -> Cookies -> Management -> Delete all
Google Chrome:
Preferences -> Under the Hood -> Clear Browsing Data -> Select the time frame and check only "Delete cookies and other site and plug-in data" -> Clear Browsing Data
Safari:
Safari -> Preferences -> Security -> Security tab -> Show Cookies -> Remove All
It is a good idea to clear your browser's cookies on a regular basis.