Force cache reload for object from browser

[Paul Bryson <Atamido@xxxxxxxxx>]

I am wondering if there is any way (standard or not) to get a web 
browser to force a web cache to check for an updated version of an 
object. I'm using a Squid proxy that I do not have control over, and I'm 
trying to grab a file from a website, but the cache keeps handing me an 
older version of the file. (A .zip file, so it is saved by the browser 
to be opened in an external application.)

If this were a webpage, it's pretty standard with browsers to hit 
Ctrl-F5 to tell the proxy to grab a new version.  But with files that 
aren't loaded in the browser, is there any way to tell it to grab a 
newer version?


Atamido