After adjusting the trigger on my CZ, I could still feel grit in the let off. Since the CZ trigger is quite open, I took some JB bore cleaner and put it on the surfaces. I suppose I worked the action a dozen or so times and then used aerosol brake cleaner to clean the surfaces. After looking at the surfaces, I could see clearly shiny areas and the gritting let off was gone.
I was extremely careful to keep the JB out of the rest of the trigger mechanism. It reduced the pull by a few ounces and smoothed things out very well.