@PKSullivan I use an electrolysis tank to strip cast iron. It is easy to build and will take old seasoning and rust off the cast iron without damaging the pan. All you really need is a manual battery charger (not a smart charger), a bucket or plastic bin, arm and hammer washing soda (laundry not baking) and an anode (I use a stainless steel bowl from the thrift store). The washing soda makes the water conduct electricity I use a 1/2 a cup per 5 gallon bucket. The red clip goes onto the anode the black clip goes on the pan and the electricity takes the rust and old seasoning towards the anode. The pan then gets a good scrub with bar keepers friend and a stainless scrubber, then a scrub with dawn, but it should come out completely stripped of old seasoning and rust. I currently have an 8" skillet in the tank that has been there for 3 days just bubbling away.
I have used the polishing method with the paint stripper wheel, and also the wire wheel method but found that while it removes old seasoning and rust and will smooth out rough cast iron, the pans are very difficult to re-season afterwards. If I get a pan that is not collectible and I feel is rough, I will use very abrasive sand paper 40-80 grit to remove the roughness but not smooth it out to the point it will no longer take the seasoning. I leave some texture and only remove the roughness. I had to do this with my Craycourt griddles for the Go-Anywhere.
When I get them stripped and cleaned, then it is time to re-season with vegetable oil at 450 for 1 -2 hours in the oven or the Weber Q220 checked with the inferred thermometer. I apply the vegtable oil then wipe off all I can. You want thin coats that can cure. Too thick and it takes longer than the 1-2 hours to cure, gets sticky and will flake off. I usually go 5-6 thin coats of seasoning sometimes up to 10.