Looking at one of my circuits (the one that had neutral and hot reversed), I found that the connection between the old cloth-insulated wiring and the newer plastic-insulated run had been made with some kind of crimped connector which included a washer that a wirenut-like plastic cover snapped over.
It looked like someone might have soldered that joint as well, though I couldn't be sure.
Alas, I don't have a photo.
Does anyone recognize this beast from the description, and is it just something that went into and out if fashion, or was there an actual reason for making the connection this way?