Do you ever print web pages, or make PDFs, and wish you could get rid of that ugly header or footer with the monster URL? By default, that information is included to show the source of the document, but it's rarely helpful and generally not pretty. I recently learned how to get rid of it in Firefox. Go to File > Page Setup … then click the Margins & Header/Footer tab
You can set all 4 of the margins, and change the drop-down menus for headers & footers to show what you want to appear.As you can see, I have small margins set, and no content appearing for headers and footers. So if I print something from, say, Google Docs, it will be nice and clean. Yes, I was tempted to use the term "clear margins" as the post title, but … yuck. You're welcome.