(from Paperthin's upgrade documentation)
For supported versions of Mozilla Firefox, you can access these options through Tools -> Clear Private Data or Tools -> Options -> Privacy. Review browser Help for more information.
For Microsoft Internet Explorer 8, click F12 -> Cache -> Clear Browser Cache or click Internet Options -> General ->Settings ->View Files -> Delete .js and .css files Note: For IE8 CTRL-R will not clear .js or .css files.
For Microsoft Internet Explorer 7, use CTRL-F5 or click Tools -> Internet Options. Under the General tab - Browsing History, click Delete. Review browser Help for more information.