Any suggestions?

So I’ve tried BKF, CLS, 50/50 vinegar water brought to a boil, and good old fashioned elbow grease, but nothing seems to do the trick. Salt pitting seems like the only explanation, but I don’t believe I cooked anything that would have led to that?

I don’t actually really care about how it looks if it’s still fine to cook on, but I just want to be sure it is in fact fine to cook on. Any help is welcome, and sorry for yet another “is my pan okay?” post.