I suggest inserting the following into the FAQ, either preceding the section on clearing cache or appended immediately after:
Performing a Forced Reload or Refresh
Ordinarily reloading a web page by clicking on the Reload or Refresh button (some browsers use hotkeys such as "Ctrl-R") ought to retrieve the current version of the web page and replace the page in the browser's cache with the new version. Under some circumstances this does not occur; either due to the manner in which the locally cached content is accessed, or because an ISP's proxy server is serving a similar older version of the page.
Most browsers can be sent a particular command, called a forced reload, to disregard the cache and instruct a proxy server to disregard its cache and retrieve a fresh copy of the relevant page. The command is normally accessed using a hotkey or macro and is usually similar or the same for a specific browser, rather than specific to an operating system. So the hotkey to force reload a page in Firefox will be the same regardless of whether it runs on Windows or Linux.
Firefox, Netscape, Mozilla/Seamonkey (all versions, all platforms) Reload = Ctrl-R or the Reload button Forced Reload = Ctrl-F5
Internet Explorer (4.0 and above, Windows) Reload = Ctrl-R or the Refresh button Forced Reload = Ctrl-F5
Opera (all versions, all platforms) Reload = Ctrl-R or the Reload button Forced Reload = Ctrl-F5
Safari (Apple MacOS) Reload = the Refresh button Forced Reload = Apple-R
Apple (other browsers) Reload = the Refresh button Forced Reload = Apple-R Most browsers running on the Apple platform will also accept Apple's hotkeys, in addition to their own. Plus some older versions of Safari were not able to perform a forced reload at all.
Linux, BSD and various types of UNIX In addition to the hotkeys specified by individual browsers, the F5 key is often an ordinary Reload.
Miscellaneous A cross-platform and cross-browser hotkey for a forced reload may be available by pressing the Ctrl-Shift keys and clicking the Refresh or Reload button.
-: A delimiter character to show a key sequence, the hyphen (minus sign) is not intended here
Apple: the Apple or command key on a Mac
Ctrl: the control key
F5: the F5 key (5th function key)
R: the letter "R" key, it does not indicate upper case (i.e. pressing the Caps Lock key or pressing Shift, unless Shift is specifically mentioned)
Shift: the shift key
That should cover around 99% of users quite thoroughly.