I have just purchased a new hard-nitriding cast iron skillet at a HomeGoods store (Brandani brand), and i'm having problems cleaning it before the first use. I've spent hours and hours washing it with soap, subbing with steel cloth, scrubbing more with salt and oil, and yet every time i dry it and then slide wet paper towel across, it gets black residue. The surface looks sliver'ish not dark, no idea why it emits dark residue, and why it still emits it after literally hours of washing and cleaning. Any ideas?
Also, despite saying it's cast iron, it feels more like thick carbon steel.
UPDATE: I ended up returning the skillet; my main concern is that Brandani brand is not known much and there is no guarantee the material (wherever it's carbon steel or some composite) is safe, as it feels like a Chinese knock off.