If firefox is banned or not available like in my office you are stuck with appending the chars manually. That´s what I thought. A avid reader of my blog mentioned the blockstop coral cdn frontend to me and it is working nicely. It reminds me a lot of those web proxy sites. Enter a url, click get url and a blockstop frame appears above the sites content of the url that you want to visit.

This is not a proxy of course but a way to access cached pages through a web frontend without installing software on your computer or entering the url and extension manually. I will try this one when I´am at work today. (we only have Internet Explorer and many websites are locked out from the network) Please let me know if this is working for your special case and if you witness any limitations or drawbacks.