Drain scale buildup

I have a 80 year old house in Pittsburgh with orig drains. I have cleaned most of them out but for instance in a 4 ft verticle drain pipe there appears to be "buildup" on the sides that is literally like cement. the pipes that I can "see" are cast iron. Not sure what is horizontal underground, could be terra cotta. How do I remove that buildup? It is also present in the tub drain pipe going into the drum traps next to the tubs. thanks