Breaking out a section of Cast Iron Pipe

[LazyPup]

When breaking out a vertical section of cast iron pipe it is best to open a cleanout below the section Then take a large wad of rags, tie a twine or wire around them and stuff in the pipe below the cleanout to catch any shards or pieces that may fall down inside the pipe. When your finished breaking out, remove the pieces, then pull the rags and replace cleanout cap.

A word of caution here...cast iron pipe is very heavy. Before breaking out a section make sure the sections that will remain are adequately supported. This can be especially important when breaking out a section of a vent riser. Make sure the pipe above the break point is supported by strapping before breaking out.

[Redwood]

I would cut out the lower section with a diamond blade in an angle grinder then plug the pipe to avoid dropping chunks of the pipe down inside the pipe creating problems below when breaking off the upper sections of the pipe.