
I can't get this pan clean
About 30 minutes after cooking, I sprayed all the food bits off the pan with hot water. I scrubbed as hard as I could for a few minutes with hot soapy water. I rinsed it all off. I scrubbed as hard as I could for a few minutes with hot soapy water again. I rinsed it all off. I dried it thoroughly with a cloth towel. I squirted a few drops of canola oil onto a paper towel and rubbed it in. The paper towel looks like this.
After I dried it but before I rubbed the oil in, it had a slightly metallic or acidic odor? Also, yes, I recently ruined the seasoning by leaving tomato sauce in it for a few days. I've used it several times since then. I've been told here not to worry about that because the seasoning will come and go?
I feel like this isn't clean and I don't know how I could possibly make it cleaner. What's going on here?