If you have accidentally applied markings with permanent marker on your whiteboard, they can be removed with ethanol, methylated spirit or isopropanol; for marking applied with paint markers, use a benzine cleaner, for example. Please keep in mind that edding permanent marker or paint marker can only be removed from smooth, non-porous surfaces.
We recommend you test on an inconspicuous area first to see if the surface is sensitive to the solvent.
For suitable products for whiteboards, have a look at our whiteboard marker range.