First, I do not use this on actual chalk boards. So I can't speak for how great they are for them.I do, however, use them on glass. I have a calendar that has a black glitter background that has glass over top. The first few tries took some shaking and pushing of the chisel to get the liquid to flow good enough to write consistently. After that, I have used the same marker to fill my calendar out for about a year.If I ever see that it seems a little dry, I push the tip in and then shake it vigorously and then make little circles on the glass until it starts flowing again. I can see the white from across the room and stays until I wipe it off.Clean up is easy! Comes right off with a finger wipe or I use a wet (windex) paper towel.
Rating: [5 of 5 Stars!]