How to Restore Your Whiteboard
Clean Erasers
Clean your dry erasers of as much marker dust as possible by brushing, beating, and washing. Many cleaning problems start with a dirty eraser. If you decide to use a felt eraser over recommended microfiber cloths, be sure to beat them out and take a vacuum hose to it as well to get as much dust out as possible. Your eraser will suddenly be much more effective.
Use Microfiber Cloths
Erase your whiteboard painted wall with a microfiber cloth. If you run into stubborn marks, don't sweat it. An affordable soy-based whiteboard paint cleaner will almost always do the trick.
Use A Soy-Based Cleaner
Clean your whiteboard painted with a whiteboard cleaner and paper towel. If you can't get ahold of whiteboard cleaner, just use a damp cloth. Don't substitute in other cleaners, as many of them will simply strip off more of the essential coating that allows you to erase the markers. Always use gentle or soft towels. Never use abrasive pads or scrubbers!
Test the marker on a small corner of the board. Make a few marks with a dry erase paint marker, then wait 10-15 minutes before trying to erase. If you did it all successfully, and the board isn't beyond repair, the marker should wipe off easily even after all of this time to dry.