I edit a newsletter for the retiree organization of my former employer. Often when I receive a draft copy of the newsletter in Microsoft Word format, I find that some paragraphs have a gray background or other formatting that I need to remove. I can't remove that grey background by changing the fill for the paragraph to "none", but I can remove it by highlighting the paragraph and then clearing the formatting. The procedure for doing so with Microsoft Word version 14.0, which is part of Microsoft Office Professional 2010, and other versions on a Windows system is to right-click on the paragraph after highlighting it, then select Styles and then Clear Formatting. The font selection will also be cleared.
Alternatively, with the text in the paragraph highligthed, hit the Ctrl key and spacebar simultaneously to clear the formatting for the paragraph.