Developer website: Thomas Dixon
ScreenClean is a very simple app that fades your screen out to a color of your choice (default is white) in order to help you physically clean your monitor.
The app also has the option of fading immediately from one specified color to another (say, from red to black) in order to help you spot stuck pixels with LCD screens. Simply click with your mouse to make the overlay disappear and return your screen to normal.
App released under the MIT license (source is included), icon(s) released under the LGPL.