I'm very stingy about installing Firefox extensions but one that made my short list is called Nuke Anything. Simply put, it lets you right click on something in a web page and remove it. I use it almost every time I print a web page to save on both ink and paper. Even web pages that aren't printer-friendly (and there are all too many of them) can be sculpted, if you will, reduce their paper and ink requirements.
Nuke Anything can remove both text and images. To remove text, first select it, then right click and chose the "Remove selection" option. To remove an image, as shown below, simply right click on it and select "Remove this object".
One small annoyance used to be that when you right clicked without first making a selection, you never knew exactly what was being removed. This was never fatal, there always was an "Undo last Remove" option (see above). A recent upgrade to the add-on introduced a brief blinking red outline around the section/object about to be removed. You can see this red border in the screen shot above.
Despite the name, Nuke Anything can not remove everything. Right clicking on a Flash movie for example, produces the Flash right click menu rather than that for Nuke Anything. Still, I find it invaluable. Perhaps you will too.