To quickly dump the cache on most browsers try (clicking an open area of your browser, i.e. not with the focus on a dialog box)...
(Command/Control) + Shift + (Delete/Backspace)
Take care to only delete or clear the cache and not your passwords or other items you might wish to retain.
Hope this works for you
Dave
This probably does not work with Safari.
[Maybe dump cookies? Probably not all.]