I bought a new Lodge DO and wanted to unseason it. I did this successfully in my oven on the cleaning cycle. It worked great. Be careful with this, as I've heard CI can warp at high temps. Mine did not.
Other options include a Lye bath or use oven cleaner and soak in trash bags (I think oven cleaner is lye based).
I think an electrolosys bath may work too. I knot it is used for rust, not sure on stripping old seasoning.