First of all a properly seasoned cast iron pan can and should be washed with modern dishwashing liquid. If the seasoning comes off with 'hand friendly ' soap it was garbage seasoning anyway.
Second, this looks perfectly ready for seasoning. Nothing wrong with that. Just get the outdoor grill going grab some short chain oil and get to work.
coat that sucker with avocado oil and bring it up to 200°C for a few minutes. Allow it to cool, repeat until the sides don't hold any oil, then switch to crisco solid shortening for a few rounds.
There's a lot of answers here, but I don't think anyone said the magic words. To reseason cast iron, you need an oil high in poly-unsaturated fatty acids. Those are the kind that can chain together, and form a good polymer coating.
The thing that trips me up most about this subject is that 140 years ago, pork fat was very good for seasoning cast iron. Today, it isn't, because the composition of the fat has changed significantly.
The best seasoning coats will be thin, not appear or feel oily, give the pan a dark color slightly more glossy than an eggshell, and resist mild detergents, metal spatulas, and heat high enough to sear a steak on. If you have a layer of loose stuff in the pan, that's just a layer of gunk, and is probably adding some weird flavors to anything you cook.
I love my cast iron pan, but I really cannot get the perfect sheen that everyone else seems to get. The bottom of mine is non-stick now, and I season regularly, but the sides always seem to chip away eventually. Once the chipping starts, I have no idea how to stop other than to strip it entirely and start again.
I've got one that I need someone to do this to so I can start over. It's older than I am and was poorly taken care of for several years before I got it.
The cast iron I bought for myself is all in good condition. That one means a lot because of where it comes from but I don't have the patience to scrape all that shit off. I wish someone would do it for me so I could enjoy the pan my grandaddy cooked me bacon in.