How and why to clear the Cache

Often referred to as the cache, the Temporary Internet Files folder contains a kind of travel record of the items you have seen, heard, or downloaded from the Web, including images, sounds, Web pages, even cookies. Typically these items are stored in the Temporary Internet Files folder.

Storing these files in your cache can make browsing the Web faster because it usually takes your computer less time to display a Web page when it can call up some of the page's elements or even the entire page from your local Temporary Internet Files folder.
How to clear the Internet Explorer cache

Each time you access a file through your web browser, the browser caches (stores) it. In this way, the files (including any images on the page) do not have to be retrieved anew from the remote web site each time you click the Back or Forward buttons. You should periodically clear the cache to allow your browser to function more efficiently.

How to clear other web browser's cache