Home was built in the 1950s, and this is where there was originally a shop in the back of a basement garage. We just tore out the wall that had been put up here (sometime in the 80s?) and were surprised by all of the loose ends that hadn't been properly closed/sealed by whoever remodeled.
There is a fireplace on the floor above this and the pink insulation on the left is where the ash/soot clean-out door was for that. We recently installed a gas insert (you can just barely see the hole for the gas line at the very top of the picture), so we don't really need to collect ashes anymore.
The cereal box taped over the bricks is covering a flue that I just removed some black stove pipe from (you can see through the large round hole on the right the terra cotta flue that the stove pipe went up into from the bottom; I don't understand why that round hole is there since there is no way to get into the terra cotta flue, which I assume is original). I do not know what the stove pipe was originally for, but it might be related to the copper pipes.
The concrete wall is about a foot behind the cinder block wall. I tried to stick my phone in the hole and get an image of the pipes from inside, but there are some old soda cans and mortar in the bottom, so I couldn't get an image of the copper pipes from inside the wall. I tried sticking my shop-vac hose back there, but couldn't loosen it enough.
The bigger copper pipe is connected to the smaller copper pipe on the left. I put compressed air in the smaller one, and got about 2 quarts of water out the big one. The water seemed to have lots of tiny metals shavings. Putting compressed air in the smaller pipe on the right didn't do anything, but when I released it, I could hear water sloshing as the air rushed back out to equalize.
From what I can tell, all three pipes gradually bend downward, but I'm not sure. I tried pushing a straightened wire hanger into the bigger pipe, and could only get it about 3 feet in. This was before using compressed air, and the wire hanger came out completely dry.
What were these pipes for, and what should I do before covering them with a stud wall and drywall, etc.?