Clearing Cache will remove any searched confidential information left on your computer

Removing your cache only clears the temporary files, that are used when you visit websites. So as you visit this website, all the graphics and pages are put in to a cache, for a quicker loading site.

What is not deleted is things you enter in to forms, your searching history, cookies and other things.

Each browser is different, but you have to find the options inside the tools menu to delete all of these things, if you want everything deleted.