I've received a wok as a gift from a Chinese lady which has a silvery/grey, sort of graphite-y coating. By graphite-y I mean it's similar in colour and shine to lead from a pencil. I can't seem to remove it! The coating comes off pretty easily onto my hands and paper towels. I've tried to clean it off by cleaning it with hot soapy water and a green scourer, heating it on a high flame for a few minutes and swishing some vegetable oil around for ten minutes or so (producing a LOT of smoke), then washing it again with boiling water and the scourer, and finally wiping dry with paper towels. The coating still persists! I haven't cooked anything in it yet.
The brand is KTL Kitchenware (can't find anything online), and looks quote rustic; round bottom, fairly thin and reasonably light — my guess it's steel (not cast iron) but I'm not sure. It looks almost hand-hammered, the texture being quite rough on the inside, with what *looks like* paintbrush strokes. Both handles are welded on and have no plastic or wooden parts.
1. I've never come across a coating such as this on any cookware, but I'm only a home cook. Does it sound familiar?
2. Do you think I need to scrub it harder/longer/burn it in more to remove it? I'm concerned about getting it in my food.
3. Does it sound safe?
Any thoughts and advice is appreciated!
*The paper towel image below was after about half-dozen rubs with a dry towel on a dry wok, after my attempted seasoning.