Best way to clean nickel plated cast iron frying pan

I have a nickel plated frying pan that has very dark mottled stains that will not come out with abrasives (copper scrubbies) and typical kitchen cleaners. I would like to restore the finish to its original brightness. I have caustic (sodium hydroxide with emulsifiers and surfactants) as well as acid blend used in the brewing industry. In the brewery, I usually clean with caustic and then passivate the stainless vessels but I don't know how nickel will react and I have seen that you can strip nickel with acids. Is it safe to expose this to hot caustic and will that do the job?

Try 2 mll sulfuric acid/100 mll pure alcohol mixture.Be careful-use rubber gloves and safety goggles.Neutralize with baking soda [in bulk on eBay or Amazon [affil link] and then rinse well.Hope it helps and good luck!