Cleaning a Water Damaged Skillet?

I found my large skillet with lid way back under the sink, which had slowly (for months) filled with water from a slow leak. I managed to wipe away (warm water and dishsoap) most of the rusty gunk, but small black spots (pits?) remain around the lid and a couple places inside. Is it too late to try baking soda or other things?

By stephanie r.