The one thing that annoys me like crazy: the high pitched squeaking sound made as chalk scratches the surface of a chalkboard. To me, that is very, very annoying. Most people hate it and tried many ways to lessen the squeaky sound but nothing really works at all.
What can I do to reduce, if not eliminate, the annoying squeaking sound of chalk on chalkboard? Please do not suggest buying a whiteboard because I want to keep my chalkboard.