Evapo rust is Magic
 

well I found a old punch buried in the garage and it had some rust on it so I tried what I considered to be a snake oil product that I saw on a car show. Yikes it like magic

http://www.evaporust.com/index.html

I dunked it in over night and with no scraping or wire wheel look at results.

I have tried on some old files and same results it a great product