This uses to be my procedure:

Clean the terminals with degreaser, gasoline or diesel and a brush, then brush and soap to remove the oil products... sink the terminals on vinegar and salt solution for 4 or 5 hours ( this will eliminate rust and sulfated areas which previous cleaning process won't eliminate ), then a baking soda solution to remove acids and you will be good to go!.Brass will change a bit the color from yellow/gold to orangish but the metal will be nicelly exposed back to get good contact.

bulhead and insulators needs to be deeply cleaned too. If not, you'll get bad contacts again.

we are talking about 50 years of abuse and forgotten systems.

try to keep original terminals were is posible. The factory crimping will be allways way better than any crimp you will make at home. If some terminal needs a replacement, crimp and sold will make the best job.



I even used small 180 grit sandpaper pieces to insert and clean inside the curvatures ( inside the "claws" ) of the female terminals, one by one

but If I have had one of these on hands, maybe was used that



BTW I also get tight a bit the female outer claws with a plyer to catch tighter the male end once is inserted