Old house, severly clogged vent stack, tools dropped in
We've got a hundred or so year old three-story house with a clogged vent/soil stack. It's clogged above the bathroom, so the bathroom plumbing works, but the drains are slow as they're not vented as they should be. There is no sewer gas smell from the vent opening on the roof. By sticking a tape measure and rented camera down from the vent opening, we were able to tell that the clog is about 14 feet down--a few feet above where the 2nd floor bathroom fixtures empty into the vent. Our first thought was to have it rodded out by a professional, but the plumbers we asked were either unwilling to take their heavy rodding equipment up to our roof, or they said they were not allowed to work on a roof. (It is a flat roof, so it's not too dangerous, so we're not worried ourselves about working on it ourselves).
We decided to try to dislodge the clog ourselves by attaching two ten-foot thin pipes together and sticking that pole down to try to push through by hand. From the debris that we brought up from the pole, it appears that the clog is something like "dirt" (though it is a bit reddish, and it will stick to a magnet--it doesn't seem to be pure rust, though). The clog is quite stubborn, and we were not able to completely push through, but we did bring up a large amount through repeated rodding with the pole, and we managed to push the clog down a full two feet. At this point, though the clog was not completely broken through, I started to smell sewer gas from the vent, so I think we had almost broken the clog.
However, we then made a huge mistake, and dropped two large pieces of metal down the vent by accident. One is a piece of rebar about a foot long, and the other is something like a large drill bit or chisel about six inches long. Using the camera we rented, we could see the rebar in the pipe standing on the clog.
We have not figured out how to get these pieces out. We are pretty sure that we're close to breaking through the clog, but we fear that if we continue rodding through as we were before, these metal pieces will fall all the way down the stack, and who knows what will happen when they hit the bottom--it's probably at least a 30 foot fall, so we think they could either damage or obstruct the place where the vent stack empties into the sewer.
So far we have two ideas, and I'm not enthusiastic about either:
1) open up the cleanout in the basement, use a rented rodding machine to try to rod up through the clog (twenty or thirty feet up from the cleanout), and then hope to catch the metal pieces before they fall down into the sewer. The cleanout is in an awkward position at the floor, and the cap is old, deteriorated, and possibly sealed with lead, so we'd need a professional to take it off and replace it for us.
2) break into the wall and have a plumber replace the clogged part of the stack. One that we spoke to said the he'd replace the part from the clog up to the roof, and that it would cost near $2000. (This is what we thought we could avoid by doing the rodding ourselves). It could be that the rust in the stack is a sign that it needs to be replaced, but when we sent the camera down, we were not able to see any holes in the stack.
We're not sure if either of these solutions is clearly the right way to proceed from a plumber's perspective, or if there are any other alternatives. Any thoughts or suggestions would be greatly appreciated. Thanks much!