Firefox
Click Tools from the Firefox menubar
Click Options
Under the Advanced options, click the Network tab
Clear cache under Cached Web Content
Chrome
Click the Customize icon on browser tool bar
Select Settings, then Show advanced settings
Under Privacy, select Clear browsing data
In the dialog that appears, select the checkboxes for the types of information that you want to remove. Use the menu at the top to select the amount of data that you want to delete. Select beginning of time to delete everything.
Click Clear browsing data