Me (texting back): Yeah, today I learned that pressure washer fitted with rooter nozzles on the business end, will snake and “jet” a pipe i.e. scour it from the inside. Not cheap but might give up to five years of service. This is according to a pro who came by, free of charge. We also discussed the pipe replacement option. This is all in reference to my upstairs rusty downpipes, shared by sink and tub (we’ve worked on it). He informed me my mental model of the downpipes inside a protruding encasement was incorrect, it does something else. I was glad to have my thinking corrected.
