I got a flat-bottomed iron wok a few weeks ago at a local Asian supermarket. I seasoned it on my electric stove, based on information I googled up: heated it up, put a thin layer of peanut oil on it, turned the heat down and let it sit for 15 minutes. This worked pretty well and formed a nice dark layer, but even after cooking in the wok a couple of times, I thought the seasoning could be better, so I decided to start over.
I used soap and a sponge scourer to get most of the patina off. To get more off, vinegar seemed like a good idea, so I boiled vinegar and water in the wok for about five minutes, let it cool, and scraped most of the remaining patina off. The wok looked (almost) good as new, so I dried it and proceeded to re-season it.
I applied my original seasoning procedure, which went well, but then the trouble started. I rinsed out the wok with hot water and rubbed it with a kitchen towel. In the center (where the metal gets the hottest, presumably), some of the patina stuck to the towel, and left iron-colored spots. I tried again twice, but the problem remained.
I thought maybe cooking in the wok would build up some patina, so I stir-fried some vegetables. Then, I rinsed and wiped it, and unfortunately, black flakes came off again. I can't seem to keep the entire bottom covered in patina.
So, any thoughts? Did I ruin my wok? Did the vinegar maybe form an oil-resistant layer or something? Anything I can try, or should I just get a new wok? Thanks.