A previous owner of my house installed a 1/2" copper tube gas line through the basement wall beneath ground level to install a grill, which an owner after him removed, leaving the line buried. I found the buried portion of the line when I accidentally hit it with a pick while digging a French drain. Long story short, I now have removed all of the gas line except the portion stuck in the wall.
I avoided crushing the part of the tube inside the basement:
The outer part didn't fare so well, it twisted and crushed while attempting to pull the line through to the outside:
At this point, I just want to make sure that water and bugs can't come in through this hole. Having a flat wall as a result would be a plus but isn't strictly necessary. Complete removal also isn't strictly necessary. I can think of 3 options:
Cap the inner part of the tube and leave the outer part as it is, or try to crush it into a crimped end. This doesn't leave me with a flat wall, and the tube may fill with water from the outside, but at least none of it will come into the basement and none of it should be able to get into the wall either unless there's a crack in the tube where it's encased in concrete.
Cut the inner portion flush with the wall and fill the tube with something. Could be a little difficult to get the filling material down to the outer end, but not the end of the world.
Drill out the tube and fill the hole. This would be the cleanest look, but the most work. On top of that, the length of the remaining tube is about 2 feet and I don't know if I could get away with drilling only the tube using a metal cutting bit, or if I would need to remove some concrete too with a masonry bit (in which case I would expect the copper to interfere).
Is there a way this is normally done? The closest process I could find to this is "pipe abandonment" which normally consists of filling an underground pipe with cement, but I only see pipe abandonment mentioned when talking about industrial or commercial-scale pipes.