Permanent Removal of Basement Toilet

Hello everyone. I have an old toilet in a friends basement that they would like to remove it. They said the toilet doesn't work (I'm not sure why...) and they would just like to remove it. The floor in the basement is a concrete slab foundation and was built in the 40's, so I'm assuming a cast iron pipe is what the toilet is attached to, but I know that there may be some terra cota involved in the lines as well. I don't know if it's in line with the other sewer lines or not, so I think just concreteing over it is out of the question.

I would like to know if there is some type of a cap for this. I've not removed the toilet yet to investigate and would prefer not to until I'm ready to make the repair. I've searched the web to try to find out if there is some type of a cap available for this and can't seem to find anything. I would assume there is a flange underneath the toilet and would like to just attach a cap to it and seal it airtight. This would also allow a new toilet to be installed if they ever choose to do so in the future. Please advise!! Thanks!!!!
-J

You can go to a big box store and get a wing nut expandable plug that should fit. You place it in the flange opening and turn the wing nut to expand the plug until it is tight. Measure the old flange and test at the store with one of their flanges and the plug to be sure it works.

seal

It should be a 4" pipe at that age. Get an expansion plug with a wing nut. It will have a "flange" around the top that is supposed to rest on the pipe, but you can use a hacksaw or tinsnips to cut that flange off so the plug will insert into the pipe below the floor level. Then tighten the wing nut, or nut, securely and cement over the hole in the floor, after breaking the top of the toilet's floor flange off.