I have a favorite 12" cast iron skillet that's been in use for about fifteen years. Since I always cared for it properly, the skillet has developed a beautiful dark finish that is nonstick.
Unfortunately, I left the clean skillet on my stove to cool and the cleaning lady thought that she was being helpful by scrubbing the skillet squeaky clean. Fortunately, most of the hard-earned patina was undamaged, but there is a half-dollar size ring in the middle of the bottom that is pretty thin. Food is starting to ever-so- slightly stick in that spot when I use it for searing.
My question is, do I need to strip the entire skillet and reseason from scratch, or is there a way to concentrate on just seasoning that section of the skillet?