How to remove brass screw cap from cast iron pipe?

I have 6" CI pipe that has a 3" brass cap for clean out access. It's 40 years old. How can I remove it?
As I remember, in my old house when I had the sewer line rodded out they used a cold chisel and 3-lb hammer to push the cap part way in to break the thread seal then a large pipe wrench to screw it out.
Before I use this brute force approach are there any other methods? thanks bob
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
My brute force techn

the
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I had same problem, and ended up using brute force technique -- used a hole saw to cut a hole in the middle of the cap, then insert recip saw into hole and cut cap into pie slices that could be pried away with a pliers (be careful with recip saw when nearing the CI pipe threads). Brass is pretty soft, so this wasn't all that difficult.
HTH, Paul

the
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
In our case, the cleanout is in the middle of a section of cast iron pipe about a foot long attached on both sides with a no hub coupling. When I get around to it, instead of cutting out the brass cap, I will remove the section with the cleanout and replace it with a new section with a new cleanout cap.
--
Peace,
BobJ

"Paul" < snipped-for-privacy@mindspring.com> wrote in message
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Why don't you put a pipe wrench on it and rotate counter clockwise? You didn't say you tried that. Before trying the esoteric, try the commonplace.
--
Christopher A. Young
Join Alt-Hvac Moderated
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
The brass cap was less than 1/8" thick. I easily drilled 6 holes in one region near the square nut then hit the nut using a 3 lb. hammer. The second hit collapsed the cap inward and it split. I used a cold chisel to push the cap threads away from the CI threads and was able to break off a quarter section of the cap. A few more taps onto the cold chisel in other regions of the cap threads and I was able to unscrew the cap. Total job took less than 5 minutes.
thanks to all who responded.

the
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

HomeOwnersHub.com is a website for homeowners and building and maintenance pros. It is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.