Chalkboard paint

I saw how to make chalkboard paint on pinterest a few weeks ago and thought I would try it out. Since I used a light color it doesn't work that well but I think it will work for what I am using it for. When I erase you can still faintly see it even if I use soap and water. My purpose for now is a behavior chart with a few of the main rules. Each time they do something good they get a shape of their choice drawn under their name but if they do something bad they get it taken away. I am thinking that if they get to 25 they get a trip to the dollar tree or something like that.