To clean a painted chalkboard, remove the chalk with felt erasers, and then wipe the chalkboard down with a wet cloth. The chalkboard should be refreshed every few months to maintain durability.
Most chalk can be removed using a felt eraser or plain water. Dampen a soft cloth with water, and wash the board. If chalk has stained the board or is difficult to remove, mix 1/2 a cup of white vinegar into a gallon of warm water and use the mixture to wash the chalkboard. A soft cloth made of microfiber or lint-free cotton is recommended for washing chalkboards.
Liquid chalk markers can leave a shadow on chalkboards. To remove the stain caused by colored chalk markers, use a soft cloth that has been dampened with commercial window cleaner or commercial chalkboard cleaner. Commercial chalkboard stain erasers are also available to remove chalk stains. If chalk stains the chalkboard permanently, repainting is necessary.
Small areas that are chipped or damaged can stain easily, and should be touched up with the same chalkboard paint that was used to paint the wall. After washing or painting, allow the chalkboard to dry overnight or at least 12 hours before use. Every three to six months, the chalkboard should be completely repainted to maintain its integrity. Follow the manufacturer's instructions carefully to create a non-porous chalkboard surface that resists stains, and repaint the board anytime chipping or damage occurs.