I sometimes copy and paste some notes from websites into another document to print up for personal use. When you do this with a website you can end up with the formatting of the website page as well. Colours, bullet-points, etc., which I don't always need.
A quick way to remove this formatting is to use the keyboard shortcut: Ctrl + Shift + V when pasting. In the box that opens click on "Unformatted text" and then OK. This works in both OpenOffice and LibreOffice.
LibreOffice also gives you a right-click option. Right-click where you want your text to be placed and click on “Paste Special” then “Unformatted Text”.
OpenOffice doesn't seem to have this option but you can still switch to the unformatted text by highlighting the text, right-clicking inside the text area and clicking on “Default Formatting” in the menu.
Other options include normal paste into a basic editor like Notepad, Notepad ++ or even Windows Wordpad all which will automatically strip away the formatting.