New to this..

I just received a pepsi machine and even though it is in pretty good shape and in working order I would like to work on refurbishing it.. problem is I don't know where to start..  I was thinking it would be best to start from the inside out??  if that is right any suggestions/recommendations on how to clean the inside metal would be greatly appreciated..   it has very little rust also..   should I just clean? polish? paint?  thanks..  greg