The Erie kettle was in the lye tank for a full three weeks, and that appears to have taken most of the paint off. I took it out of the lye on Wednesday, scrubbed it with steel wool and Barkeepers Friend, and I've had it in electrolysis over the past two nights. However, I don't think my electrolysis setup is doing a good job: I can barely get 2 amps of current in my tank with the 12-volt 10-amp charger, and there have been hardly any bubbles or foam despite all of my efforts to improve it. Yesterday morning I scrubbed off a lot of black paint residue (and got it all over myself); this morning there was hardly any paint coming off, though there were still rust stains. Until I can figure out what I'm doing wrong with the electrolysis, I'm going to fill the inside with a 50-50 vinegar-water solution tonight and let it soak until tomorrow evening. That should clean up the inside, at least.
Fortunately, I haven't discovered any cracks; so the indication is this pot can be cleaned up to the point where it can safely cook again.
The markings on the bottom of the pot are more legible; there's some pitting, but not too much. The writing on the bottom can be seen as: "ERIE" PATD. MAR 19, 1891. 827 8.B.
The initial discovery of this huge 1890s-era Erie (Griswold) stovetop kettle: April 14, 2014