oh gosh I know what you mean. My son bought me my first cast iron pan, he was just a little boy and his dad took him Christmas shopping to an old general store. I abused that pan something terrible because I had no idea what I was doing, and I hated using it -- until I had that magical aha moment and then everything changed. That little pan is still busy working for me despite the early abuse.

Great question! Its something I hadn't really considered. I usually oil the whole pan, including bottom when I store them and when I season them so I do rub oil on the whole pan quite often. If you use it fairly often, I think if you gave it a gentle scrubbing, oiled it and then baked with it, over time the bottom would build up a good finish again without you having to re-season it.