A rank noobie here - really enjoying your site & forum. Good, practical, advice.
Regarding cast iron: In the past, when encountering a well-used pan, thickly encrusted with the residue of too many past meals on the outside, I've placed it into a bed of glowing coals in a fireplace, or a large fire outside as it is dying down.
Leaving the pan in the ashes 'til they've cooled down, it has to be washed, and then reseasoned just as a brand new pan would be. This needs to be done right away, as the super dry cast iron will develop a patina of rust quickly if not oiled. If the pan has had a lot of use in the past, it won't take as long to have it back in good working order as with a new pan.