Found these tips on the web:
You can click the Refresh button on the Navigation Toolbar or press "Ctrl + R" or F5 to reload a web page.
You can reload the page and bypass the cache with:
Press and hold Shift and left-click the Reload button.
Press "Ctrl + F5" or press "Ctrl + Shift + R" (Windows,Linux)
Press "Cmd + Shift + R" (MAC)