After you treat parts, do not forget to put a coating on the parts fairly quickly, to prevent rust from coming back. Nothing is more annoying than derusting a part, to find it covered in surface rust a couple of weeks later...
I have used "no-name" (i.e. very cheap) Cola for derusting parts. Parts need to be power washed after, takes a couple of days soaking. Probably not better than vinegar. Next time (if there is a next time!), I would try some sort of acid, citric or phosphoric, they seem to work better/faster.
