I've got a new office and I must clean off my inherited whiteboard. The previous owner left various diagrams, code snippets, etc. on for such a time that they can no longer be erased by conventional means: the whiteboard eraser is useless! I couldn't find any whiteboard cleaner either, but Ali told me the following secret. You can write over the dried on text with a normal dry erase marker. When you erase the new markings the old are erased as well. It sounds too fantastic, but believe me, its true! I don't know the brand or material of the whiteboard but the whiteboard markers are 'Expo, Bold Color Dry Erase'.