I just won an auction for an old cherry stoner, the kind that’s a wheel and a crank that basically mangles the pit out of the cherry. It was listed as cast iron, but there’s no way to tell for sure, otherwise I 's just treat it like my cast iron skillet. My googlefu had failed me, so what are some good options for protecting this thing from rust damage over time, while keeping it food safe? Should I just coat it in something like the wax I use for my cutting board?
Oil.
Any oil you would use on a cutting board or consider food safe.
treat all cast iron and carbon steel cookware the same. clean it good, chuck it into a pre-heated oven to dry, pull it out and coat it with the same kind of vegetable oil you’d use to season cast iron, and let it cool.
This. The trick is to clean it when you’re done, and dry it after cleaning. A light coating with a vegetable oil while it is hot is fine, but remember that will go rancid, so not too thick and make sure it’s hot enough to start burning the oil off.
You can always clean rancid and gummy vegetable oil on cast iron with oven cleaner, so you don’t need to obsess about it.
Wax will work fine and won’t turn rancid. You don’t want to burn oil onto it if you care about how it looks.
I would do oil + heat if I could be sure that it was pure cast iron, but what if it’s something else, or plated or something? Or would that not matter somehow?
Would mineral oil work for this purpose?
Yes, but it will leave a bad taste on any food it contacts. Assuming excess has been cleaned off after application not enough to be dangerous would be ingested.
What does the surface look like? Is it dark grey? (if so, it’s probably uncoated cast iron) - or is it bright silver? (in which case it’s probably nickel plated cast iron, and should only need a good clean and proper drying after use)
You’re not going to be using this for frying so forget about everything you’ve ever heard about seasoning because it does not apply. You do not want to carbonize the surface or gunk it up.
Warming it in the oven may not be a bad idea to dry it after washing, but that’s it.
A thin coating of oil, while it’s cool, is enough. That will be good for any metal.