Liquid Chalk Markers
These behave nothing like a chalk stick despite the name. The ink is a wet pigment that dries to an opaque film and wipes off non-porous surfaces such as glass, mirror and gloss laminate. On raw slate, unsealed blackboard paint or anything porous it soaks in and can stain permanently, so test an out-of-sight corner before writing a menu board. See chalk, glass boards and markers.
