I went through this and tried to document it. Started here... PNW 67 Patina Blue - https://forum.ih8mud.com/threads/pnw-67-patina-blue.1289865/page-4#post-14699350
Get your self a brake cylinder hone, oil it up, and do some light back and forth. Then do the fingernail test. If you can really feel the pits, time for new ones or a re-sleeve if you're brave and have a lot of time on your hands.
Do you have a dremel? I've been in this situation unfortunately (well, not on a crank, but a cylinder head). I had to use a hardened steel shank bit to grind the remaining metal to as close to the threads as possible, then I was was able to pick it out with a pic and some needle nose pliers. A...
I had a white 70 Mach 1 back in the mid-90s that I traded for a clapped out 74 Scout II. To be fair the Mustang was a rust bucket by hindsight why, why do you do this to me?!!!
I drove an old Chevy C10 that had a similar color scheme in high school. Donor parts from who knows what didn't, matter the color. It was nicknamed the Picasso truck by my classmates. At the time it was not so funny, looking back, it was fitting.