Carbon Black Cleaner

Has anyone ever heard of a LensPen? They are pen shaped cleaning tools that people use to clean optical surfaces like the lens of a camera. They use a carbon black compound on a cloth tip that is rubbed on the lens. It works surprisingly well even though carbon black is usually used as a dye or for reinforcing tires.

I have been trying to make a mixture of carbon black, calcium sulfate (one of the ingredients the lenspen uses) and water to create something like this for myself but I haven't been able to do it. Does anyone know anything about this? Any suggestions on quantities of each ingredient? It is very interesting to me and I want to find out more about it.