Hello, my grandmother gave me her cast iron skillets that were her mother's before. They were so gunked up around the sides and on the bottom I couldn't even tell what they were. Very well used and loved. But I figured It was time to strip them so I could put my own seasoning on them. I did some research, found that most spray on foam oven cleaner's have lye in them. Which is the main thing for stripping old seasoning off because it's oil. It turns it to a black goo on the pan that is suppose to rinse off. Well really it worked fairly well. I sprayed my pans and put them in a plastic garbage bag to hold the moisture and left them for a day. Most if the crud sloughed right off. But there was carbon build up that just didn't want to budge. I ended up getting copper wool scrubbie thing that worked wonders. I even tried a wire brissel brush. It worked well too. But oh what a task. Took me about 3 days. Probably because of being impatient and not letting the oven cleaner work long enough. But enough elbow grease and I got enough off to be happy about it. I wonder what my grandma will say when she sees all the years of seasoning gone..