Re: Distributor cap question
White crusty stuff on the terminals themselves is corrosion, and oxidation.
It probably induced by moisture and the high temperatures of ignition energy jumping to the posts.
Don't clean them with a file, use contact cleaner in a spray can, and emery cloth.
Women's emery finger nail boards and ink pins with ink erasers work pretty good too.
Those ink pins with the ink erasers on the end are the best kept secret in electrical trouble shooting.
They are long, fairly slim, and clean contacts like nothing you have ever seen before.
I always keep an eye out for freebies at the bank or hardware store, ect...
Same with finger nail emery boards, but they go south if they draw moisture or get wet.
Never leave home with out one if you have a points ignition or a GM HEI...
"I Have The Body Of A God... Buddha"