Hey, I got one too !
"How should breaker points be dressed down ? Breaker points should be dressed with an oil stone,; never with a file"
'Know your Model A Ford' by Murray Fahnestock 1930
protected by a very thin coating of platinum. once you file that off, you're down to the unprotected base metal.
Forget the oil. I use water. The stone lasts just as well and does a better job.
I have a point file someplace. Don't think I have ever used it.