Removing a cast iron soil pipe and replacing with plastic

[andy hubbard]

I have just seen the very good article on removing a cast iron soil pipe and replacing with plastic. How did the installers stop fragments of cast iron from falling inside the old stack?. Did they cut out a section at the bottom and then cover the hole?

[plumbbob]

I'm not sure how your article showed the pipe being removed, but I usually dismantle the pipe in sections from the top, separating it at the joints. This way, no debris drops down inside the pipe.