The kitchen and bathroom are back-to-back. The kitchen sink drain is the upper one and the lower one goes to the lavatory. The kitchen sink was leaking behind the cabinet and I opened it up to find this.
I'd like to replace both drains with PVC, but would rather leave that cast iron piece alone. The hubs are threaded and the threads are in decent shape, at least the ones on the top are. I haven't removed the other one yet, but assuming they are also okay, should I screw a PVC fitting into them? Or is there a better way to connect something to this?