A lot of blogs have the sidewalk chalk paint posted. We decided to give it a try. First, we sorted our old chalk by color.
Then we smashed them up with a hammer in a plastic sandwich bag.
Either our chalk was really hard, or my kids were impatient. They definitely did not get it all down to a fine dust. There were still lots of big chunks in our paint, but it seemed to work okay.
We mixed it up with some water. They liked it pretty runny.