Water optional, have just been using microfiber cloths for about 2 years now. And they barely ever need washing. Water doesn't hurt anything but if you use it you have to wait for it to dry.
Whiteboard Hack: Ever accidentally write on your white board with a permanent marker? Don't fret. Use a dry-erase marker and color over the permanent market, then wipe dry. VOILA! You just proved nothing is permanent.
He is a Chef hack for you teachers with whiteboards right in the kitchen when our whiteboard gets disgusting. We use methylated spirits and that cleans it up like it’s brand-new. I wouldn’t recommend doing it all the time, but if you can’t get it out with just this guy tip give that a try you’ll probably get there just make sure it’s dry and there’s no methylated spirits I left before you start writing on it it can’t destroy your pens and damn, they are expensive