AZ…. My fryer looked about the same.. did alot of scraping, but that only worked to a certian point.  Finally used a boil out. Add water, product, fire it up, let it boil for 30 min, the stuff just falls right off. Looks like brand new.
 
You just have to make sure to rinse very well…..You can get deep fryer cleaner at most cash & carry type places. Cost me around $6 gal.